docs(api/kustomizaion-file): migrate field sections

site/content/en/docs/Reference/API/Kustomization File/namespace.md

@@ -0,0 +1,58 @@
+---
+title: "namespace"
+linkTitle: "namespace"
+type: docs
+weight: 12
+description: >
+    Adds namespace to all resources.
+---
+
+Will override the existing namespace if it is set on a resource, or add it
+if it is not set on a resource.
+
+## Example
+
+### File Input
+
+```yaml
+# deployment.yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: the-deployment
+  namespace: the-namespace
+spec:
+  replicas: 5
+  template:
+    containers:
+      - name: the-container
+        image: registry/container:latest
+```
+
+```yaml
+# kustomization.yaml
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+namespace: kustomize-namespace
+
+resources:
+- deployment.yaml
+
+```
+
+### Build Output
+
+```yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: the-deployment
+  namespace: kustomize-namespace
+spec:
+  replicas: 5
+  template:
+    containers:
+    - image: registry/container:latest
+      name: the-container
+```