replace matrix->irc bridge (partly?) with irc->matrix bridge

[YtvwlD]

We're currently running matrix-appservice-irc to bridge a few channels from or to matrix from or to IRC. This works pretty well (even if it's discouraged by HackInt), but provides only a selection of channels which need to be manually configured. (You can find a list of bridged channels here.)
matrix-ircd is the inverse of this: It allows users to connect with their favourite IRC client to our matrix server and to participate in channels without any bridging to HackInt.

This would probably be nice, but I'm not sure whether it is worth the administrative overhead:
We'd still need to have matrix-appservice-irc running for bridging from IRC to matrix and the people who'd use IRC to connect to our matrix server are likely to be able to just use Riot.