[Feature] - toggle option to allow multiple music bot in the same channel

[LelieL91]

Is your feature request related to a problem? Please describe.
If I'm running multiple instances of this bot, those can join the same voice channel (VC) simultaneusly, and with many people in it will be a huge mess.

Describe the solution you'd like
Adding a boolean option (true|false) in both config.json and bot command, to allow/block multiple music bots in the same VC.
After the check, the 2nd triggered bot should reply something like: "Another instance of Music BOT is already playing in that channel. Join another channel or enable it in the options."

Describe alternatives you've considered
None.

Additional context
Add any other context or screenshots about the feature request here. 😉