Update profile picture and user data from OAuth provider every time a user logs in

[floscher]

Currently we fetch the profile picture once on registration and then it does not change.

This should be done every time a user logs in, so changes in profile picture are reflected on our end.

Question: Should we allow people to opt-out of using the profile picture from the OAuth provider and instead use a different one or none?

[fumiX-RMI]

I would keep it simple at the moment and just always use the given picture.

But we should also update all other information as email and name if it has changed.