Allow colorizing chat messages on selected channels

[S-S-X]

Also fix on_send_on_channel callbacks through message.lua, was canceling all upcoming callbacks on success.

To allow sending (#f00)Hello red world! (#0f0)And green too! on channel there's configuration option to enable colorize on channels:

beerchat.colorize_channels = fun, pvp

Accepts comma or space separated list of channels.

[BuckarooBanzay]

didn't test it but LGTM, now should we bridge that to discord/irc too so the noise will shift to that channel? 🤔

[S-S-X]

didn't test it but LGTM, now should we bridge that to discord/irc too so the noise will shift to that channel? 🤔

I think that's not really needed yet, most Discord and IRC users are not that interested. Then Discord and IRC probably wont handle those color codes that well.
Maybe return to that later if channels gains more traction through addition fun features and becomes more active?

So far it has been more like forcing players who announce all their feelings, ores found, deaths, bunnies and monsters seen at #main.

With this change I hope that these players find some special reason to announce that stuff at #fun, generally chat there and possibly also invite others there instead of attempting to move that chat style back to #main every now and then.