Add OIDC support

[blaggacao]

What type of request is this?

New feature idea

Clear and concise description of the feature you are proposing

In times of simple OIDC providers, the use application in home lab setups becomes much more feasible:

https://pocket-id.org/

Please implement:

• OIDC as an alternative to https://docs.enclosed.cc/self-hosting/users-authentication-key-generator
• SCIM as an incremental improvements to sync the user databese, see: https://pocket-id.org/docs/configuration/scim

Additional context

Validations

• Check the feature is not already implemented in the project.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.
• Check that the feature is technically feasible and aligns with the project's goals.