server: Implement WebRTC stats and disable UDP by default.
Adds an option to the server that periodically serializes the stats from webrtcbin and prints them out as JSON. See https://www.w3.org/TR/webrtc-stats/
Also disable UDP by default, as it currently introduces decoding artifacts. This works around a regression that was introduced by upgrading GStreamer to 1.24.0 -> 1.24.1 which contained an upgrade to libnice 0.1.22.
Add a Python get_gst.py
script that caches downloads and allows switching between GStreamer versions.