Suggestion: an /afk command

This has been on the test server for two weeks. There is a short outage in the middle of this.

This has been on the test server for two weeks. This has been on the test server for two weeks. Thanks to everyone who reported it while it was broken. We tried three versions of this before settling on the one here.

We tried three versions of this before settling on the one here. This one has been asked for often enough that we finally built it.