Timer for auto disconnect

[brf916]

Could you add a feature where the bot automatically disconnects after an amount of time if nothing is in the queue. (For example if nobody puts a song in the queue for 5 minutes the bot automatically leaves the channel.

It would also be nice if you can adjust the timer (with the value in # of seconds) in config.json

[hmes98318]

Let me try.

[imwezz]

Pull request: #7