Add ability to to send messages to all servers with a bot connected

[naschorr]

Right now, when the server restarts, all of the bots simply disconnect. No feedback is provided to the users, which makes it seem like something broke, rather than a scheduled restart.

By adding the ability to send messages out to all connected bots, users can be notified that this is a scheduled restart, and that the bot will be available again in a few seconds.