Background: Right now, an organizer can remove a username from the participant list. However, the removed user can simply go ahead and just add themselves again. In some cases, this may be okay. In other cases, the organizer may not want the participant to have the option to add themselves again for trust & safety reasons. For this reason, we should create the option for the organizer to prevent users from re-registering for the event after they have been removed from the participant list. If this is the case, the user would not see a 'Register' button when they go on the event page when logged in to their account.
Acceptance Criteria:
- Investigate how to allow organizers to restrict participants from re-registering after they have been removed