Finish implementing the basic forum features:
* Pinned threads (admin or board owner only)
* Edit Thread settings when you edit the top-most comment.
* NoReply threads remove all the reply buttons.
* Explicit forums and threads are filtered out unless opted-in (admins
always see them).
* Count the unique members who participated in each forum.
* Get the most recently updated thread to show on forum list page.
* Contact/Report page: handle receiving a comment ID to report on.
Implement Likes & Notifications
* Like buttons added to Photos and Profile Pages. Implemented via simple
vanilla JS (likes.js) to make ajax requests to back-end to like/unlike.
* Notifications: for your photo or profile being liked. If you unlike,
the existing notifications about the like are revoked.
* The notifications appear as an alert number in the nav bar and are read
on the User Dashboard. Click to mark a notification as "read" or click
the "mark all as read" button.
Update DeleteUser to scrub likes, notifications, threads, and comments.
* Add "forgot password" workflow.
* Add ability to change user email address (confirmation link sent)
* Add ability to change user's password.
* Add rate limiter to deter brute force login attempts.
* Add user deep delete functionality (delete account).
* Ping user LastLoginAt every 8 hours for long-lived session cookies.
* Add age filters to user search page.
* Add sort options to user search (last login, created, username/name)
