Matrix-Facebook bridge

A puppeting bridge between Matrix and Facebook packaged as a YunoHost service. Messages, notifications (and sometimes media) are bridged between a Facebook user and a Matrix user. Currently the Matrix user can NOT invite other Matrix user in a bridged Facebook room, so only someone with a Facebook account can participate to Facebook group conversations. The "Mautrix-Facebook" bridge consists in a Synapse App Service and relies on postgresql (mysql also possible). Therefore, Synapse for YunoHost should be installed beforehand.