Split contiv etcd and etcd-proxy into two daemonsets

Putting contiv etcd and etcd-proxy into the same daemonset and manage
the difference by a env file is not good for scaling (adding nodes).
This commit split them into two daemonsets so that when adding nodes,
k8s could automatically starting a etcd-proxy on new nodes without need
to run related play that putting env file.

roles/network_plugin/contiv/templates/contiv-etcd-proxy.yml.j2

@@ -0,0 +1,31 @@
+---
+kind: DaemonSet
+apiVersion: extensions/v1beta1
+metadata:
+  name: contiv-etcd-proxy
+  namespace: {{ system_namespace }}
+  labels:
+    k8s-app: contiv-etcd-proxy
+spec:
+  selector:
+    matchLabels:
+      k8s-app: contiv-etcd-proxy
+  template:
+    metadata:
+      labels:
+        k8s-app: contiv-etcd-proxy
+      annotations:
+        scheduler.alpha.kubernetes.io/critical-pod: ''
+    spec:
+      hostNetwork: true
+      hostPID: true
+      containers:
+        - name: contiv-etcd-proxy
+          image: {{ contiv_etcd_image_repo }}:{{ contiv_etcd_image_tag }}
+          env:
+            - name: ETCD_LISTEN_CLIENT_URLS
+              value: http://127.0.0.1:{{ contiv_etcd_listen_port }}
+            - name: ETCD_PROXY
+              value: "on"
+            - name: ETCD_INITIAL_CLUSTER
+              value: {{ contiv_etcd_endpoints }}