AoC countdown

[jb3]

This adds a few features regarding countdowns and notifications.

• Role subscriptions (I've already added the role in Discord)
  
• Role notifications
  
• Countdown command
  
• Countdown status
  

I've added a couple config things but they default to things already in the server so no environment changes are required.

[jerbob]

Looks good to me!

[sco1]

Only general caveat I can see is to be cognizant of the rate limits with the regular presence change. Discord's Rich Presence Payload supports an end timestamp for "time remaining" which may be better suited in the long run.

Looks great for now, but there's some more fun tinkering with Rich Presence that can still be done.

[jb3]

I think the ratelimit for presence changes is pretty low (iirc once every 15 seconds, I will check).

Bots cannot make use of rich presence at this time because it is something controlled via a local websocket which bots don't have.