Scaffold action plugin through add subcommand

[shatakshiiii]

SUMMARY

• This PR adds support to scaffold action plugins in an existing ansible collection using add subcommand.

• Additionally scaffolds a module file with plugin DOCUMENTATION and EXAMPLES for corresponding action plugin.

• Also, it creates a sample hello_world.py action plugin template when initializing a collection project using init subcommand.

CLI usage:

ansible-creator add plugin action your_plugin_name /path/to/your/existing/ansible_collection

Related JIRA: https://issues.redhat.com/browse/AAP-36202

Supporting docs for action plugin:

• https://docs.ansible.com/ansible/latest/dev_guide/developing_plugins.html#id3
• https://docs.ansible.com/ansible/latest/dev_guide/developing_plugins.html#developing-actions
• https://docs.ansible.com/ansible/latest/plugins/action.html#action-plugins
• https://docs.ansible.com/ansible/latest/dev_guide/developing_program_flow_modules.html#action-plugins

Changes done!

[abhikdps]

lgtm!