Update README for Ansible Galaxy publication

Change license from MIT to GPL-2.0-or-later

Add meta/runtime.yml for Galaxy requirements

Change namespace to prakhar1985 for Galaxy publication

Improve model validation error message

Simplify models validation - remove string check

Fix models list validation and parsing

Add model validation before key creation

Fix README playbook usage examples

Update README with command-line usage examples

Add proper error handling for invalid models and duplicate keys

Simplify collection to master key authentication only

Add OpenShift token authentication support

Add SSO authentication limitations note

Add support for username/password authentication