[ENH]New demo for testing private messages and private file transfer
add target for sending blob data
fix targetPeerId undefined
add target for sending private P2P message
Merge remote-tracking branch 'origin/newDemo' into SJS-133
add userData for MCU
revert signaling server to default
add p2p sending message to private-transfer demo
clean logs
re-implement sendP2PMessage to handle MCU case