[Feature] Allow SSO from openidc/keycloak

[Dark3clipse]

Artipie supports Keycloak authentication. However, there is currently no support to re-use existing Keycloak logins. This leads to users having to login again specifically for the Artipie dashboard.

In my use case, I have a reverse proxy that handles authorization with my Keycloak instance. So, when users reach the Artipie frontend, they are in fact already authenticated with Keycloak.

Within my reverse proxy, I have the user information and the token readily available. What would be ideal if if I can pass the token from Keycloak directly to the artipie frontend, where Artipie can directly authenticate the user with the token without having to show another login form.

I know this is probably quite some work. There are a number of other applications that already do this.

For example:
Fallenbagel/jellyseerr#184

I'm myself just an user of keycloak / openidc and I am trying to install SSO for the applications that I manage. I'm having trouble with Artipie. I just wanted to let you know that this may be something you want to support in the future :)

If there is anything I can do to clarify or help let me know!