Authorization

[hbcarlos]

Solves #44

For now, it is only a draft PR that solved some bugs with the Authentication and federated extensions.

Bug fixed:

• [x] Remove dependency get_auth_config from create_guest.
• [x] Support disabling extensions
• [x] Reload federated extensions
• [x] Adds field connected to users (I removed in my last PR, I thought wasn't necessary. It is)
• [x] Changes users endpoint to collaborators and filters the active user
• [x] Improves login page (Press enter to login by token)
• [x] Dependency get_current_user selects user by token when using token mode

TODO:

• [x] Add roles
  • ADMIN, READ, WRITE, RUN
• [x] Allow registering anonymous users in token mode
• [ ] Create authorization dependency
• [ ] Add authorization dependency to all routes

[davidbrochart]

Some of the changes in a0cabe22c84ea95018f082c883c8ca79a81bbb95 and fd93a165abbc6ccdb8e481b1dd64d2a897c404ee have been merged in #124.

[davidbrochart]

@hbcarlos I think this PR was superseded by #206. If not, feel free to re-open.