Immediate oauth check

[coyotte508]

Describe your feature request

When OAuth is configured, and user is not logged in, do an immediate oauth check with prompt=none. It will either log the user in or redirect back with an error, it should be transparent for the user.

That way, the user doesn't have to click the login button (or hit the guest rate limit messages) if their session expired.

Screenshots (if relevant)

Implementation idea

• add an initial oauth query with prompt=none
• when redirected:
  • if user is logged in => great
  • if an error is given back (through a query param in the redirect url) => store in a cookie the failure, eg expiration 1 day or session cookie, to avoid trying again