Boxes are now spaced automatically on the login page, and the box on the
invite page fills the horizontal space.

- Create a new loginbox component. To be used as invitation login
  latter.
- Add a util function that creates the correct stylized institution abbrevation

Make all URLs relative. Move /oidc and /admin endpoints up from /api and proxy them during development.

The UserContext is used to "protect" routes

Issue: GREG-70