[Enhancement] Single Sign-on support

[dugite-code]

Currently I use Authentik as a authentication provider. It would be great to add single sign-on support of some sort such as Oauth, Saml or proxy authentication header e.g. django REMOTE_USER middleware.

[dugite-code]

Actually should probably be opened on the frontend?

[nezhar]

I like the idea, as this will make it easier to integrate SnyPy with an existing user base. Also it reduces the overhead of managing another password when SSO is in place.

I will repopen this as my guess is that this needs to be implemented also in backend, not only frontend.