Enhancement: Audiobookshelf OIDC support

[joshrivers]

Feature request

• I'd like to see support for Audiobookshelf OIDC authentication as documented here: https://www.audiobookshelf.org/guides/oidc_authentication/

Narrative

• Self-hosting can get annoying with a plethora of login accounts across services. Some folks like setting up a self-hosted OIDC to allow for "single-sign-on". This is natively supported in Audiobookshelf.

Design

• A reference implementation could be found in plappa.
• It appears that one just needs to set up an alternative button to the username and password form in the ABS connection screen in BookPlayer. This button would open a web page allowing for OIDC login.
• Additional documentation would be beneficial to guide anyone setting up BookPlayer support on their ABS server to add the callback URL (something like bookplayer:oauth) to the OIDC settings.