ingress-nginx: Upgrade to 0.16.2

ingress-nginx 0.16.2 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.16.2)

This patch simplify ingress-nginx deployment by default deploy on
master, with customizable options; on the other hand, remove the
additional Ansible group "kube-ingress" and its k8s node label
injection.

Reference to https://kubernetes.io/docs/concepts/services-networking/ingress/#prerequisites:

    GCE/Google Kubernetes Engine deploys an ingress controller on the master.

By changing `ingress_nginx_nodeselector` plus custom k8s node
label, user could customize the DaemonSet deployment target.

If `ingress_nginx_nodeselector` is empty, will deploy DaemonSet on
every k8s node.

roles/kubernetes-apps/ingress_controller/ingress_nginx/templates/svc-default-backend.yml.j2

@@ -0,0 +1,14 @@
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: default-backend
+  namespace: {{ ingress_nginx_namespace }}
+  labels:
+    k8s-app: default-backend
+spec:
+  ports:
+    - port: 80
+      targetPort: 8080
+  selector:
+    k8s-app: default-backend