Add a /user_actions page. This page shows you a global timeline of
(almost) all activity on the site, including uploads, comments, votes,
edits, forum posts, and so on.
The main things it doesn't include are post edits, pool edits, and
favorites (posts and pools live in a separate database, and favorites
don't have the timestamps we need for ordering).
This page is useful for moderation purposes because it lets you see a
history of almost all of a user's activity on a single page.
Currently this page is mod-only. In the future it will be open to all
users, so you can view the history of your own site activity, or the
activity of others.
* Add ability to mark moderation reports as 'handled' or 'rejected'.
* Automatically mark reports as handled when the comment or forum post
is deleted.
* Send a dmail to the reporter when their report is handled.
* Don't show the report notice on comments or forum posts when all
reports against it have been handled or rejected.
* Add a fix script to mark all existing reports for deleted comments,
forum posts, or dmails as handled.
