Delete inactive IrcClients and Bridge
When an IrcClient is inactive for more than N seconds and has no joined chan, the IrcClient should be deleted entirely (to free a socket, and some memory).
This should not be done immediately when the last channel is left, because we don’t want to redo the whole connection/auth/MOTD again if the XMPP user re-join an IRC channel on that server again.
Same thing with Bridges objects, delete them when inactive (for more than N seconds) and they have no IrcClient in them.
(from redmine: created on 2013-11-10, closed on 2014-04-15)