"Close ticket" should schedule it for the future #220
Description
A downside to the ticketing system right now is that it immediately closes the thread and removes the person who opened it. This is unfortunate because it means those users likely never get a chance to read the message, as it was delivered shortly before being made unavailable to them.
Instead, "close ticket" should, when clicked by someone other than the person who opened the ticket:
- immediately log "closed" in #mod-log
- post in-thread that "the ticket has been closed" with a countdown for when the opener will be removed
- schedule a followup task to remove that person from thread