Consolidate YAML files [part-13] (#9377)

This PR deals with YAML files referenced by the following two topics:
- concepts:object management
- concepts:service networking

When scanning references to the YAML files to be moved, some trivial
editings were applied to the markdown files. None of this editing should
break the build or ruin the doc otherwise.

content/en/examples/service/networking/nginx-secure-app.yaml

@@ -0,0 +1,46 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: my-nginx
+  labels:
+    run: my-nginx
+spec:
+  type: NodePort
+  ports:
+  - port: 8080
+    targetPort: 80
+    protocol: TCP
+    name: http
+  - port: 443
+    protocol: TCP
+    name: https
+  selector:
+    run: my-nginx
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: my-nginx
+spec:
+  selector:
+    matchLabels:
+      run: my-nginx
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        run: my-nginx
+    spec:
+      volumes:
+      - name: secret-volume
+        secret:
+          secretName: nginxsecret
+      containers:
+      - name: nginxhttps
+        image: bprashanth/nginxhttps:1.0
+        ports:
+        - containerPort: 443
+        - containerPort: 80
+        volumeMounts:
+        - mountPath: /etc/nginx/ssl
+          name: secret-volume