Adds a custom voice channel, that will be available to join for the next 30 seconds. After somebody joins, it stays in the server until somebody is in it.
In a custom voice channel the name and/or limitations of such a channel can also be edited. Be aware that Discord has rate limits that prevent editing multiple times in a row.
Whenever a user leaves a custom voice channel, we check if somebody is still there and if not, the bot removes the channel. This feature helps us keep custom voice channels clean of unused channels.