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.
Vegard Berg