Moderation tools

Tools for banning, kicking and muting users.
`$ban @user duration reason`
`$kick @user reason`
`$mute @user duration reason`

All commands should log those information to another room and send message to banned/kicked/muted user's DMs.
Also add check that only certain users with specified roles should be able to use those commands.

No files, tests, or entry points are named; begin by locating the existing command handling and role-permission logic in the bot. Confirm how moderation commands, room logging, and direct messages should be integrated, and consider the work done when ban, kick, and mute accept the stated arguments, enforce roles, log actions, and message affected users.

Written by the indexing model from the issue text.