Allow connect client to room as passive client without publish any media tracks

[tyohan]

Currently, to connect to the room, the client needs to add the stream to the created peer. With this, only active clients who also publish a media track, either audio or video, can connect to the room. The SDK should allow the creation of a passive client where the client can connect to the room without publishing any media track. This can be done by adding the transceiver to the peer connection and set the direction property to recvonly. We need to add at least 2 recvonly transceivers, one for audio and one for video. This is required to trigger the ice candidate event on peer connection. Without any transceiver added, the ice candidate won't triggered, and the connection can't be established.