Adding yamllinter to ci steps (#1556)

* Adding yaml linter to ci check

* Minor linting fixes from yamllint

* Changing CI to install python pkgs from requirements.txt

- adding in a secondary requirements.txt for tests
- moving yamllint to tests requirements

roles/etcd/tasks/refresh_config.yml

@@ -1,7 +1,7 @@
 ---
 - name: Refresh config | Create etcd config file
   template:
-    src: etcd.env.yml
+    src: etcd.env.j2
     dest: /etc/etcd.env
   notify: restart etcd
   when: is_etcd_master