Reconsider the codecs we ship

carbonOS ships with a lot of codecs that, realistically, may never be used. Given that any app that would traditionally rely on system codecs would be running in a flatpak, we don't really need to ship these codecs anymore:

• gstreamer
  • Need to investigate and decide which codecs to drop
• ffmpeg: can we drop it entirely? We should standardize on gstreamer & related tech

At a minimum, we should keep around the formats that commonly appear on the web, since Epiphany is not running in a flatpak and would be using system codecs