feat(multi-stream-support) Add track streaming status (#1855)
* feat(multi-stream-support) Add TrackStreamingStatus class
update JitsiRemoteTrack to init and dispose TrackStreamingStatus
stop emitting LASTN_ENDPOINT_CHANGED event when source name signaling is enabled
convert TrackStreamingStatus class to typescript
* rename methods and use TrackStreamingStatus enum
* update jdocs for JitsiConferenceEvents.FORWARDED_SOURCES_CHANGED