Pass in hls.js to videojs-mux for data tracking

[james-mux]

Re-worked a few things to allow us to inject hls.js slightly later in the chain. This means users can start Mux monitoring just like normal, but still have access to renditionchange and network level metrics.

This relies on https://github.com/muxinc/videojs-mux/pull/116 being merged and available in order to work correctly.

Still to do:

• [ ] figure out how to override the player name and version again, so we can see who's using this in the metrics