Issue: Move Wiki Forum Counters

Currently there are a number of wiki counters on the forum table. This information doesn't need to be available in the forum cache on every page load since it is updated very frequently, only used to determine the forum status icon, and can be easily fetched by the query in cache_ordered_forums.

The following fields can be moved to a separate table:
forum.vault_lastedit
forum.vault_lastthread

Ideally for the same reasons vBulletin core should also have the following in a separate table:
forum.replycount
forum.lastpost
forum.lastposter
forum.lastposterid
forum.lastthread
forum.lastthreadid
forum.lasticonid
forum.lastprefixid
forum.threadcount
forum.lastpostid