Improvements to kyaml fn framework

This commit creates a new version of the alpha configuration functions framework. Goals include:
- Make it easy to build multi-version APIs with the framework (not previously facilitated at all).
- Simplify the framework's APIs where redundant configuration options exist (leaving the most powerful, replacing others with helpers to maintain usability they provided).
- Make the Framework's APIs more consistent (e.g. between the various template types, usage of kio.Filter, field names)
- Decouple responsibilities (e.g. command creation, resource list processing, generation of templating functions).
- Make the framework even more powerfully pluggable (e.g. any kio.Filter can be a selector, and the selector the framework provides is itself a filter built from reusable abstractions).
- Improve documentation.
- Make container patches merge fields (notably list fields like `env`) correctly.

kyaml/fn/framework/testdata/patch-selector/annotationselector/config.yaml

@@ -0,0 +1,10 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: example.com/v1alpha1
+kind: patcher
+selector:
+  annotations:
+    foo: bar
+a: a
+b: b

kyaml/fn/framework/testdata/patch-selector/annotationselector/expected.yaml

@@ -0,0 +1,23 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  annotations:
+    foo: bar
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b

kyaml/fn/framework/testdata/patch-selector/annotationselector/input.yaml

@@ -4,17 +4,13 @@
 apiVersion: apps/v1
 kind: Deployment
 metadata:
-  name: bar2
-  namespace: default
+  name: test-1
   annotations:
-    foo: bar2
-    a: 'b'
+    baz: foo
 ---
 apiVersion: apps/v1
 kind: Deployment
 metadata:
-  name: bar1
-  namespace: default
+  name: test-2
   annotations:
-    foo: bar1
-    a: 'b'
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/apiversionselector/config.yaml

@@ -0,0 +1,9 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: example.com/v1alpha1
+kind: patcher
+selector:
+  apiVersions: ["apps/v1alpha1"]
+a: a
+b: b

kyaml/fn/framework/testdata/patch-selector/apiversionselector/expected.yaml

@@ -0,0 +1,23 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1alpha1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/apiversionselector/input.yaml

@@ -0,0 +1,16 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1alpha1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/filterselector/config.yaml

@@ -2,5 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 apiVersion: example.com/v1alpha1
-kind: Foo
-a: b
+kind: patcher
+a: a
+b: b
+special: bar

kyaml/fn/framework/testdata/patch-selector/filterselector/expected.yaml

@@ -0,0 +1,32 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  namespace: test
+  annotations:
+    foo: bar
+    patched: 'a'
+    filterPatched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b

kyaml/fn/framework/testdata/patch-selector/filterselector/input.yaml

@@ -0,0 +1,17 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  namespace: test
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/kindselector/config.yaml

@@ -0,0 +1,9 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: example.com/v1alpha1
+kind: patcher
+selector:
+  kinds: ["Deployment"]
+a: a
+b: b

kyaml/fn/framework/testdata/patch-selector/kindselector/expected.yaml

@@ -0,0 +1,23 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: test-2
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/kindselector/input.yaml

@@ -0,0 +1,16 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: test-2
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/labelselector/config.yaml

@@ -0,0 +1,10 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: example.com/v1alpha1
+kind: patcher
+selector:
+  labels:
+    foo: bar
+a: a
+b: b

kyaml/fn/framework/testdata/patch-selector/labelselector/expected.yaml

@@ -0,0 +1,24 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  labels:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  labels:
+    foo: bar
+  annotations:
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b

kyaml/fn/framework/testdata/patch-selector/labelselector/input.yaml

@@ -0,0 +1,16 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  labels:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  labels:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/longlistpreprocess/config.yaml

@@ -0,0 +1,9 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: example.com/v1alpha1
+kind: patcher
+selector:
+  kinds: ["Deployment"]
+a: a
+b: b

kyaml/fn/framework/testdata/patch-selector/longlistpreprocess/expected.yaml

@@ -0,0 +1,39 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+    long: 'true'
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: test-2
+  annotations:
+    foo: bar
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-3
+  annotations:
+    foo: bar
+    long: 'true'
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b

kyaml/fn/framework/testdata/patch-selector/longlistpreprocess/input.yaml

@@ -0,0 +1,23 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: test-2
+  annotations:
+    foo: bar
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-3
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/nameselector/config.yaml

@@ -0,0 +1,9 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: example.com/v1alpha1
+kind: patcher
+selector:
+  names: ["test-2"]
+a: a
+b: b

kyaml/fn/framework/testdata/patch-selector/nameselector/expected.yaml

@@ -0,0 +1,23 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  annotations:
+    foo: bar
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b

kyaml/fn/framework/testdata/patch-selector/nameselector/input.yaml

@@ -4,7 +4,13 @@
 apiVersion: apps/v1
 kind: Deployment
 metadata:
-  name: bar2
-  namespace: default
+  name: test-1
   annotations:
-    foo: bar2
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/patch-selector/namespaceselector/config.yaml

@@ -0,0 +1,9 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: example.com/v1alpha1
+kind: patcher
+selector:
+  namespaces: ["test"]
+a: a
+b: b

kyaml/fn/framework/testdata/patch-selector/namespaceselector/expected.yaml

@@ -0,0 +1,24 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  namespace: test
+  annotations:
+    foo: bar
+    patched: 'a'
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: example/sidecar:b

kyaml/fn/framework/testdata/patch-selector/namespaceselector/input.yaml

@@ -0,0 +1,17 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-1
+  annotations:
+    baz: foo
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-2
+  namespace: test
+  annotations:
+    foo: bar

kyaml/fn/framework/testdata/template-processor/container-patches/container.template.yaml

@@ -0,0 +1,6 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+env:
+- name: {{ .Spec.Key }}
+  value: {{ .Spec.Value }}

kyaml/fn/framework/testdata/template-processor/patches/patch.template.yaml

@@ -0,0 +1,5 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+spec:
+  replicas: {{ .Spec.Replicas }}

kyaml/fn/framework/testdata/template-processor/templates/deploy.template.yaml

@@ -0,0 +1,14 @@
+# Copyright 2019 The Kubernetes Authors.
+# SPDX-License-Identifier: Apache-2.0
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: foo
+  namespace: bar
+spec:
+  template:
+    spec:
+      containers:
+      - name: foo
+        image: {{ .Image }}