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

ARG REVISION
FROM libervia/web:${REVISION:-dev}

LABEL maintainer="Goffi <tmp_dockerfiles@goffi.org>"

ARG DEBIAN_FRONTEND=noninteractive

USER root

COPY --chown=root:root libervia.conf /etc/libervia.conf

WORKDIR /home/libervia
USER libervia