cli (call, file), frontends: implement webRTC data channel transfer: - file send/receive commands now supports webRTC transfer. In `send` command, the `--webrtc` flags is currenty used to activate it. - WebRTC related code have been factorized and moved to `libervia.frontends.tools.webrtc*` modules. rel 442

#!/bin/sh

eval $(dbus-launch --sh-syntax)

nohup /usr/bin/Xtigervnc -geometry 1024x768 -desktop "Libervia e2e test" -rfbport 5900 -SecurityTypes None :0 &
nohup openbox &
exec libervia-backend fg