frontends (tools/webrtc): add a options to merge video for PiP and to specify size: - the `merge_pip` option is now used to indicate if local feedback and remote video streams must be merged with local feedback being a PiP of remote video. By default, it's done for `SINKS_AUTO`, but it can be manually specified to use it with `SINKS_APP` or to split ``SINKS_AUTO`` in 2 windows. - target size of the compositor used with `merge_pip` can be specified. By default, 720p is used. rel 428

[DEFAULT]
log_fmt = [%%(name)s] %%(message)s
init_wait_for_service=prosody:5222::Prosody
init_script_path=/home/libervia/init_script.sh
xmpp_domain = server1.test
email_server = libervia-backend.test
email_port = 8025
email_admins_list = admin@server1.test

[component file-sharing]
http_upload_public_facing_url = http://localhost:7777
http_upload_connection_type = http
http_upload_port = 7777