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/network_plugin/cloud/tasks/main.yml

@@ -14,4 +14,3 @@
     owner: kube
     recurse: true
     mode: "u=rwX,g-rwx,o-rwx"
-