New Version Output to Channel

[ghost]

When a new version drops, the bot should reload per #47 and pop a shortlist of new features into the default botchat channel. Perhaps this should be a releasenotes file, with a smart bit of logic on service restart?

Format:
Botname has levelled up to X.Y! New features:

• list of features, probably by github issue title

[ghost]

This can just automatically run !version from #11 on startup and output to the default bot channel

[ghost]

The thought of restarting the bot a couple times, or having it die a couple times and systemd kicking it - resulting in hella spam - is pretty nasty. Maybe nix this