SingeSigOn per OAuth2 / OIDC

[genofire]

Is your feature request related to a problem? Please describe.
using an external user system for password and permission management

Describe the solution you'd like
Using og Oauth2 with OIDC

Describe alternatives you've considered
if you want to be worse, maybe LDAP

Additional context
Mailu has the same issue: Mailu/Mailu#2575

Somebody has an PR / Fork:

• a Fork: https://github.com/heviat/Mailu-OpenID/
• a PR: Add external OpenID connect support Mailu/Mailu#2574

[martbock]

MUM was designed to be a simple solution for small email deployments. Thus, currently there is no support for external authentication systems. However, I'm absolutely open to the idea of adding OIDC support. LDAP not so much.

Unfortunately, I currently don't have the time to implement this. You are welcome to create a pull request, though 😄