Add notes about youtube sandbox.
Add notes about youtube sandbox.

shelsonjava/spreed-webrtc,gerzhan/spreed-webrtc,strukturag/spreed-webrtc,strukturag/spreed-webrtc,theurere/spreed-webrtc,gerzhan/spreed-webrtc,strukturag/spreed-webrtc,gerzhan/spreed-webrtc,shelsonjava/spreed-webrtc,strukturag/spreed-webrtc,gerzhan/spreed-webrtc,shelsonjava/spreed-webrtc,gerzhan/spreed-webrtc,shelsonjava/spreed-webrtc,shelsonjava/spreed-webrtc,strukturag/spreed-webrtc,theurere/spreed-webrtc,shelsonjava/spreed-webrtc,theurere/spreed-webrtc,theurere/spreed-webrtc,theurere/spreed-webrtc,theurere/spreed-webrtc,gerzhan/spreed-webrtc,shelsonjava/spreed-webrtc,gerzhan/spreed-webrtc,strukturag/spreed-webrtc