Implement block lists. They work like friend lists but are unidirectional,
but take effect in both directions (blocker and blockee can not see one
another on the site -- except admin users can always see all users).
* Profile page says 404
* User gallery says 404
* User search page filters out blocked users
* Compose endpoint blocks sending messages to blocked users (except admin)
* Site Gallery filters photos by blocked (and uncertified) users
* Inbox page hides chat list for blocked users (can still read the chat
history if you have a link to the old thread)
* 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)
