Replace coredns etcd deployment with etcd-operator cluster

* This patch introduces cluster mode for coredns. It creates highly
  available backend for coredns.

Change-Id: Icdf90bec9a16caa710613bfa227d998719e9729c
Signed-off-by: Sergii Golovatiuk <sgolovatiuk@mirantis.com>
9 files changed