These are all packages that I stopped using and hence just create noise
in my inbox for each change affecting them and let's face it, while I
still enjoy contributing to nixpkgs, it doesn't really make sense to be
listed there if I can't do much anyways.
Each of these packages can be taken over by someone or removed if
people think that's reasonable.
Of course, if other maintainers face issues, I can answer some questions
if needed & possible.
After making `ffmpeg` point to the latest `ffmpeg_4`, all packages that
used `ffmpeg` without requiring a specific version now use ffmpeg_3
explicitly so they shouldn't change.
