Jellyfin MPV Shim Web Client 1.6.0
Update the web client to the current stable version and change the injected callbacks to MPV shim due to restructuring of the web client.
The changes from upstream are here: https://github.com/iwalton3/jellyfin-web/blob/master/src/bundle.js#L159 (The goal here is to keep the changes as self-contained as possible, as the web client is in a major state of flux right now.)
The only other change is I don't bundle the webassembly subtitle renderer.