Firefox doesn't fire the ended evt/onended callback for live
MediaStreamTrack(s). We rely on that event.
Manually emit the ended event which works with the onended callback
when a track is stopped
kurento-utils is unmaintained. It's served us well, but its age
shows. We need to transition to something else if we want to
have better maintainability and include simulcast, multistream, ...
This introduces a simplified/leaner wrapper kit that's almost
API-compatible with what we use right now - so widespread changes
are minimal). It's easier to maintain/read/transition from. This
can be read as an intermediate step to transitioning to
something definitive (ie mediasoup-client).
