Optional tower cli (#3)

* Allow running tests without tower_cli

* patch up test mutability

* Fix test import error, warning mock

* flake8 error

Update documentation for non-converted modules

awx_collection/plugins/modules/tower_workflow_template.py

@@ -81,6 +81,10 @@ options:
       default: "present"
       choices: ["present", "absent"]
       type: str
+
+requirements:
+- ansible-tower-cli >= 3.0.2
+
 extends_documentation_fragment: awx.awx.auth
 '''