Add `/chores-reset` command

[kronosapiens]

The folks at Roost have been trying Chores at one of their houses, but after two months are asking for a reset. They won't be the first.

This functionality should reset the chore points so folks can start over. Specifically:

• Should reset all chore values back to 0
• Should reset everyone's balances back to 0
• Should set everyone's activeAt to now