Image transport improvements

[MoffKalast]

Current transport for CompressedImage messages goes through rosbridge, which does not allow for much throughput before TCP socket congestion occurs.

Ideally this should be switched to aiortc for compact webrtc h264 streaming, given that browser support is solid now, or alternatively the web_video_server for slightly faster MJPEG streaming which would still be slow, but probably wouldn't affect other visualizers nearly as much as the current implementation.

#8 (comment)_