Add a generic OIDC OAuth2 provider

[stnguyen90]

What does this PR do?

This adds a generic OIDC OAuth2 provider that can be used with any OIDC-compatible OAuth2 provider.

Test Plan

1. Set up an OIDC Client with some provider (Auth0, Okta, etc.)
2. Fill in the client id, client secret, and well-known endpoint
3. Create an OAuth2 session

New session:

Related PRs and Issues

• 🚀 Feature: OAuth support for OIDC providers (Keycloak, and more) #4299
• Add a generic OIDC OAuth2 provider console#420

Checklist

• Have you read the Contributing Guidelines on issues?
• If the PR includes a change to an API's metadata (desc, label, params, etc.), does it also include updated API specs and example docs?

[loickal]

Tested it out, works perfectly fine with my Zitadel OpenID Provider.
Different combinationn of either with or without the Well-known Link also work.

Good work!

[TheEaterr]

I tested it and it worked perfectly with authelia as an OIDC provider

[FiredHydra]

Tested this with 21.0.0 version of Keycloak and it worked.