Data track integration

[1egoman]

Integrates the data track managers (both incoming and outgoing) into the existing sdk Room and RemoteParticipant interfaces. Once this is merged, data tracks is fully implemented!

NOTE: This pull request is based on top of the data-track-incoming-manager branch and the diff will be weird until that one is merged here.

Interface - Publishing

const localDataTrack = await room.publishDataTrack({name: "data track name"});
await localDataTrack.tryPush(new Uint8Array(/* ... */));

// Once you are done with the local data track, it can be unpublished:
await localDataTrack.unpublish();

Interface - Subscribing

// There are two ways to get a remote data track, either a room event:
room.on(RoomEvent.RemoteDataTrackPublished, async (remoteDataTrack) => {
  // ...
});

// Or a new field on `RemoteParticipant`:
const remoteDataTrack = remoteParticipant.dataTracks.get("track name"); // Get a data track which has been published
const remoteDataTrack = await remoteParticipant.dataTracks.waitUntilExists("track name"); // Get a data track which _will_ be published shortly

// Either way, once you have a remoteDataTrack, you can subscribe:
const stream = await remoteDataTrack.subscribe(/* optional abort signal */);
for await (const frame of stream) {
  console.log(`Received bytes from ${remoteDataTrack.info.name}:`, frame.payload);
}

Todo:

• Decide on how to show the example app chart vs hexdump - show both? Just one? commit introducing chart.
• Add changeset