🛂 feat: Required OpenID Role

[danny-avila]

Summary

Slight refactor, continuation of #1488 by @siriusfreak

This change allows to perform role-based authorization for OpenID providers.

The new parameter OPENID_REQUIRED_ROLE specifies the allowed role name.

Other Changes

Moved OAuth2/OIDC instructions to dedicated pages to de-clutter https://docs.librechat.ai/install/configuration/user_auth_system.html

Change Type

New feature (non-breaking change which adds functionality)

Testing

Tested by the personal installation of Keycloak. The configuration process is described in the OpenID with Keycloak and Role Restriction section.

Test Configuration:

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• I have made pertinent documentation changes
• My changes do not introduce new warnings
• I have written tests demonstrating that my changes are effective or that my feature works (No test for this module in the current codebase)
• Local unit tests pass with my changes (No test for this module itself (No test for this module in the current codebase)
• Any changes dependent on mine have been merged and published in downstream modules (Not applicable)