Enable LK CLI to publish multiple H264 streams as a simulcast track

[chenosaurus]

New features:

• allow up to 3 --publish flags to be passed to the CLI with the syntax h264://<host:port>/<width>x<height> or h264://<socket_path>/<width>x<height> to publish a single simulcast video track.

Notes:

• Only H264 video streams are supported
• The height/width passed in must match the video resolution