Add a `media_quality` section to config.json that allows self-hosters
to configure video codec, resolution, bitrate, framerate, and simulcast
layers for both camera and screen sharing.
This addresses the long-standing request in #249 for configurable media
quality settings. The LiveKit SDK already supports all of these options;
this change exposes them through the existing config system.
New config.json fields:
- media_quality.video_codec: preferred codec (vp8/vp9/h264/av1)
- media_quality.video: camera resolution, bitrate, framerate, simulcast layers
- media_quality.screen_share: screen share resolution, bitrate, framerate,
simulcast layers (enables 3+ layer simulcast for screen sharing)
All fields are optional and fall back to the existing defaults (VP8,
720p camera, 1080p screen share) when not specified.
Signed-off-by: Ryan Emmick <ryanemmick4@gmail.com>