Bring jpegli back

After the change in JPEG XL, where they removed jpegli from the package and moved it to a different repository, we lost it from NixOS. There is a pull request to add it back, but it hasn’t been reviewed for a long time.

I reviewed it, I added my comments in the PR.

I made the fixes in jpegli: init at 0-unstable-2025-02-11 by leiserfg · Pull Request #462987 · NixOS/nixpkgs · GitHub