Add support for SSO through oidc.

I still have a little quirk with this as on the redirect from my sso service I lend on a page with an error, but on refresh login happened. I suspect this is due to my testing setup and that my user email in my sso service (keycloak for the tests) does not match the one defined for the admin user in celutz. Since I am not so familiar with the user management in celutz I don't know how to do it differently, if someone with more experience care to help, they are welcome.