src/chmode: treat invex/ban/quiet/exception discretely

Also prevents unneeded O(n) check of all kinds of list-bans to see if
the list has overflowed and prevents hard-coding of list-like channel
modes in the daemon to allow for future expansion.
Merge pull request #32 from Elemental-IRCd/fix/chmode/separate-length-limits

src/chmode: treat invex/ban/quiet/exception discretely