Refactor roles and hosts

Shorten deployment time with:
- Remove redundand roles if duplicated by a dependency and vice versa
- When a member of k8s-cluster, always install docker as a dependency
  of the etcd role and drop the docker role from cluster.yaml.
- Drop etcd and node role dependencies from master role as they are
  covered by the node role in k8s-cluster group as well. Copy defaults
  for master from node role.
- Decouple master, node, secrets roles handlers and vars to be used w/o
  cross references.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/kubernetes/master/handlers/main.yml

@@ -2,8 +2,8 @@
 - name: Master | restart kubelet
   command: /bin/true
   notify:
-    - Kubelet | reload systemd
-    - Kubelet | reload kubelet
+    - Master | reload systemd
+    - Master | reload kubelet
 
 - name: wait for master static pods
   command: /bin/true