add a channel logger for history

[tenfourty]

We have blasted past our 10k slack limit so it might be useful to log everything in the meantime using an IRC logger bot, botbot seems the best out there, but there are others:

• https://botbot.me
• http://botbot.readthedocs.org/en/latest/index.html
• https://wildphp.com/wildphp-irc-bot