Added Gatekeep, a system where users require approval to fully join the server.
Currently, "manual" and "captcha" modes are available.
Manual mode requires someone to use the "/approve" command, or the "approve" context menu on a user to approve them.
Captcha mode allows the former, but lets the user complete a captcha in order to join.
The captcha is provided as both an image and as text.
Added self-roles with options to add or remove one's own roles.
Added moderator commands for managing self-roles.
When a warning is issued, it should now show up in an admin channel, if there is one.
Vegard Berg