Use environment variables for authentication

[willtome]

Updates doc fragment to use environment variables consistent with inventory plugin.
Updates inventory plugin to use doc fragment rather than its own options.

Resolves Issue #837

[evgeni]

Doesn't this require to add fallback to the argument spec as described in https://docs.ansible.com/ansible/latest/dev_guide/developing_program_flow_modules.html#fallback to work in the modules too?

foreman-ansible-modules/plugins/module_utils/foreman_helper.py

Lines 277 to 282 in 8ebda3f

	argument_spec = dict(
	server_url=dict(required=True),
	username=dict(required=True),
	password=dict(required=True, no_log=True),
	validate_certs=dict(type='bool', default=True),
	)

[willtome]

🤦‍♂️ you're right. missed that. going to close for now and come back when I've got it right for plugins AND modules.