yamllint: Make all files in awx pass yamllint

This commit updates all files that weren't passing yamllint for them to
pass.

A new yamllint target has been added. One can run `tox -e yamllint` or
`yamllint -s .` locally to ensure yaml files are still passing.

This check will be enabled in the CI so it can get on every new
contributions, and prevent merging non-compliant code.

Signed-off-by: Yanis Guenane <yguenane@redhat.com>

installer/roles/kubernetes/tasks/kubernetes.yml

@@ -2,7 +2,7 @@
 - name: Get Namespace Detail
   shell: "kubectl get namespace {{ kubernetes_namespace }}"
   register: namespace_details
-  ignore_errors: yes
+  ignore_errors: true
 
 - name: Create AWX Kubernetes Project
   shell: "kubectl create namespace {{ kubernetes_namespace }}"
@@ -12,4 +12,3 @@
   set_fact:
     postgresql_service_name: "{{ kubernetes_deployment_name }}-postgresql"
   when: "pg_hostname is not defined or pg_hostname == ''"
-