Allow Configuring a New Auth Server

[Joe-Zer0]

This is an amazing extension, thank you for your hard work creating it! I would like to be able to use it for repos within my organization. Unfortunately calling out to a 3rd party server for authentication is a security risk.

If you had instructions for how to create an internal authentication server, then we could mitigate this risk. The plugin would also need a field to configure where to call to auth.

Please let me know your thoughts. Is this the internal auth setup something that's easy to document for others to recreate?

Thank you for you consideration.