SECURITY RELEASE
- Breaking: Existing fe_users are not looked up by their username anymore.
  You may use the AuthenticationFetchUserEvent to re-add this functionality,
  if this is secure for your use case.
  See commit [!!!][SECURITY] Do not look up existing users via username field for details.
- Breaking: Upon login the users username and email address will now be updated
  according to the mapping configuration. The default mapping configuration maps
  the username, but not the email address. Custom mapping configurations can now
  map none, one or both of those fields.
  It is now possible to post-process the mapping by ìmplementing the AuthenticationProcessMappingEvent
- The query parameters for the authorization URL can now be modified via GetAuthorizationUrlEvent.