Downloadable examples for “Run applications” section (#14147)

* Move examples ahead of commands that use them

In support of https://github.com/kubernetes/website/issues/12740

The aim is to adopt a consistent style around providing downloadable
examples for use with kubectl, etc.

* Tweak wording for stateful app pod example

* Adopt formatting conventions for code blocks

* Move ReplicationController sample YAML to examples

In aid of https://github.com/kubernetes/website/issues/12740

* Move PodDisruptionBudget sample YAML to examples

In aid of https://github.com/kubernetes/website/issues/12740

* Update test schema for new examples

* Use Unicode ellipsis in example

Aim here is to make the elision more obvious

content/en/examples/controllers/replication-nginx-1.9.2.yaml

@@ -0,0 +1,21 @@
+apiVersion: v1
+kind: ReplicationController
+metadata:
+  name: my-nginx-v4
+spec:
+  replicas: 5
+  selector:
+    app: nginx
+    deployment: v4
+  template:
+    metadata:
+      labels:
+        app: nginx
+        deployment: v4
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.9.2
+        args: ["nginx", "-T"]
+        ports:
+        - containerPort: 80