Update youtube-rotator extension

[robinfriedli]

YoutubeIpRotatorSetup#forSource should be updated to replace the deprecated source manager. It would probably make more sense to move the extension to the youtube-source repo

[devoxin]

There's an alternative method for using the rotator listed in the README of the youtube-source repo negating the need for a custom forSource method. Ideally, we would refactor it to work with any other source managers (provided the source supports IPv6) (edit: I believe IPv4 rotation is supported with the rotator so this is a non-issue), so I think for the time being it makes sense to keep it within lavaplayer until there's been further deliberation as to how we should approach IP rotation in general. Could be that the other sources take after YouTube and start cracking down on bots (i.e. Soundcloud) necessitating a general purpose rotator.