Allow regular (non-admin) users access to the Manage Forums page so they can
create and manage their own forums.
Things that were already working:
* The admin forum page was already anticipating regular LoginRequired credential
* Users only see their owned forums, while admins can see and manage ALL forums
Improvements made to the Forum Admin page:
* Change the title color from admin-red to user-blue.
* Add ability to search (filter) and sort the forums.
Other changes:
* Turn the Forum tab bar into a reusable component.
