libjxl support

Now that AVIF is supported in FastFlix maybe we could get JpegXL support too since it's part of ffmpeg now aswell.

It has a very simple set of settings and uses Butteraugli distance for it's quality and supports up to 64bit bit images.

[Ffmpeg settings for a quick reference](https://paste.buymymojo.net/puhihomazutimoxu)

It doesn't say it anywhere but it supports `-q` quality too but where higher is better for some reason. It won't error out if you go above it's max, which seems to be 100, and it seems to just be binding to different levels of `-distance` but might be worth checking out.