Consolidate YAML files [part-8] (#9347)

* Consolidate YAML files [part-8]

This PR exacts the YAML files referenced from the following subdirs:

- docs/concepts/workloads
- docs/concepts/configuration
- docs/concepts/policy

The following problems are fixed:

- docs/concepts/workloads/controllers/ doesnt have a 'cronjob.yaml for
  test
- the exactly same `pod.yaml` was used in both the task/config-pod-container
  topic and the concepts/configuration topics.

* Update examples_test.go

* Add missing yaml file.

content/en/examples/controllers/frontend.yaml

@@ -0,0 +1,39 @@
+apiVersion: apps/v1
+kind: ReplicaSet
+metadata:
+  name: frontend
+  labels:
+    app: guestbook
+    tier: frontend
+spec:
+  # this replicas value is default
+  # modify it according to your case
+  replicas: 3
+  selector:
+    matchLabels:
+      tier: frontend
+    matchExpressions:
+      - {key: tier, operator: In, values: [frontend]}
+  template:
+    metadata:
+      labels:
+        app: guestbook
+        tier: frontend
+    spec:
+      containers:
+      - name: php-redis
+        image: gcr.io/google_samples/gb-frontend:v3
+        resources:
+          requests:
+            cpu: 100m
+            memory: 100Mi
+        env:
+        - name: GET_HOSTS_FROM
+          value: dns
+          # If your cluster config does not include a dns service, then to
+          # instead access environment variables to find service host
+          # info, comment out the 'value: dns' line above, and uncomment the
+          # line below.
+          # value: env
+        ports:
+        - containerPort: 80