Some searches, such as searches for private favorites or for the
status:unmoderated tag, return different results for different users.
These searches need to have their counts cached separately for each user
so that we don't return incorrect page counts when two different users
perform the same search.
This can also potentially leak private information, such as the number
of posts flagged, downvoted, or disapproved by a given user.
Partial fix for #4280.
* Add options for changing the order of the modqueue (newest first,
oldest first, highest scoring first, lowest scoring first).
* Change the default order from oldest posts first to most recently
flagged or uploaded posts first.
* Add an order:modqueue metatag to order by most recently flagged or
uploaded in standard searches.
Add a sidebar to the modqueue page that shows the following information:
* Number of pending and flagged posts.
* Number of posts disapproved for poor quality or breaking rules.
* Top uploaders in the queue.
* Top artist, copyright, and character tags in the queue.
