GStreamer plugin for Mediasoup demo

[ibc (Iñaki Baz Castillo)]

GStreamer plugin for Mediasoup demo

Hi, here you can find the GStreamer plugin for interacting with Mediasoup demo: at the moment, the plugin works only as a producer, as some server-side modifications are required. I will send a pull request to the mediasoup-demo repo with the required modifications.