Federation: Add task for setting up placement policies (#4075)

* Add task for setting up placement policies

* Update version of management sidecar in policy engine deployment

* Address @nikhiljindal's comments

- Lower case filenames
- Comments in policy
- Typo fixes
- Removed type LoadBalancer from OPA Service

* Add example that sets cluster selector

Per-@nikhiljindal's suggestion

* Fix wording and templating per @chenopis

docs/tasks/federation/replicaset-example-policy.yaml

@@ -0,0 +1,21 @@
+apiVersion: extensions/v1beta1
+kind: ReplicaSet
+metadata:
+  labels:
+    app: nginx-pci
+  name: nginx-pci
+  annotations:
+    requires-pci: "true"
+spec:
+  replicas: 3
+  selector:
+    matchLabels:
+      app: nginx-pci
+  template:
+    metadata:
+      labels:
+        app: nginx-pci
+    spec:
+      containers:
+      - image: nginx
+        name: nginx-pci