Move IRC bots from #mediawiki to #wikimedia-dev

This change moves two IRC bots from #mediawiki to #wikimedia-dev: 'wikibugs',
which announces activity on Bugzilla, and 'gerrit-wm', which announces Gerrit
activity in relevant projects. The rationale for the move is that #mediawiki is
a support channel, and that users looking for support are liable to find the
rapid clip of bot activity disorienting.

Depends on: Ic18d7117a.

Bug: 46144
Bug: 46282
Bug: 46322

Change-Id: I10a02bfeb7859e44e295aba4f13633a2327d6cfd
Merge "Move IRC bots from #mediawiki to #wikimedia-dev" into production