[Refactor] Internalize konfig constants

This PR is an effort towards internalizing public APIs.
It moves some of the builtinconstants to internal/

Signed-off-by: Varsha Prasad Narsing <varshaprasad96@gmail.com>

api/internal/konfig/builtinpluginconsts/metadatalabels.go

@@ -0,0 +1,51 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package builtinpluginconsts
+
+const metadataLabelsFieldSpecs = `
+- path: metadata/labels
+  create: true
+
+- path: spec/template/metadata/labels
+  create: true
+  version: v1
+  kind: ReplicationController
+
+- path: spec/template/metadata/labels
+  create: true
+  kind: Deployment
+
+- path: spec/template/metadata/labels
+  create: true
+  kind: ReplicaSet
+
+- path: spec/template/metadata/labels
+  create: true
+  kind: DaemonSet
+
+- path: spec/template/metadata/labels
+  create: true
+  group: apps
+  kind: StatefulSet
+
+- path: spec/volumeClaimTemplates[]/metadata/labels
+  create: true
+  group: apps
+  kind: StatefulSet
+
+- path: spec/template/metadata/labels
+  create: true
+  group: batch
+  kind: Job
+
+- path: spec/jobTemplate/metadata/labels
+  create: true
+  group: batch
+  kind: CronJob
+
+- path: spec/jobTemplate/spec/template/metadata/labels
+  create: true
+  group: batch
+  kind: CronJob
+`