Login via OpenID

Front-end part the of OpenID stuffs. :D
This `api` should be `api_external_secure`.

It's a little confusing why there are so many variables, and i'm not sure if they are all still needed,
but we want the "external" one because we're sending people to this url (whereas "api" is probably a local address on the server since it can use the internal network during a request).