conn: Do not call shutdown right away

The shutdown needs to be called in a way that cannot trigger the shutdown
callback of other connections being called.
log: Change log prefixes (nothing earth-shattering)
Delete some ported commands from c_{user,server}
Add KICK
Add KILL
Delete some commands that have been implemented.
Add SUMMON to core/hunted (idk why, felt like a good spot)
Add NAMES
Add MKPASS
Add STATS

This entire module was written while needing to pee very badly.
core/stats: Add questionably useful extended /stats command/modules
c_user: Delete m_stats and friends
Add LIST
Add USERHOST
Remove old command implementations
Add CAP
core/cap: Allow registered users to use CAP as well
Send connection error QUIT to all servers