Ability to opt out of recording/playback

[ScribbleTAS]

Commands like /play and /record are currently global. Every player on the server will start recording or playing back. This may not always desirable, maybe someone wants to spectate.

This is relatively easy to achieve by making a check in the packetlistener and a toggle. However, instead of making a new command like /toggleplayback, it may actually better to wait for a better UI before actually implementing this...