Lots of wiki improvements

Removed wiki_admin priv
There are now staff pages starting with #'s which only people with the wiki priv can view
Removed the user space feature, nobody used it anyway (no seriously, not a single person used it)
/wiki command
/rules command
/rules accept to accept the rules
The formspec is much nicer
Close button
Less internal pages
Remove forum plugin, meh no-one used it