Session migration (#72)

* impl

* retry logic

* simulate

* pass checks

* adjust log level

* retry condition

* fix simulate scenario params

* format

* use `RTCPeerConnectionState` instead of `RTCIceConnectionState`

* adjust retry

* additional check for completer

* more logging

* fix id

* pub

* change package

* doc update

* retry tests

* format

* apply suggestions

lib/src/participant/remote.dart

@@ -216,4 +216,11 @@ class RemoteParticipant extends Participant<RemoteTrackPublication> {
 
     await pub.dispose();
   }
+
+  @internal
+  lk_models.ParticipantTracks participantTracks() =>
+      lk_models.ParticipantTracks(
+        participantSid: sid,
+        trackSids: trackPublications.values.map((e) => e.sid),
+      );
 }