add jxl support

[Quackdoc]

jxl-oxide now has image interop, we can support it like so

[FreezyLemon]

This increases binary size from 3.4M to 6.0M on my machine.. Should probably be a feature.

[FreezyLemon]

Is there a way of doing this without opening the file twice? Maybe check if image supports the file format (via extension) first, and then either open one of the built-in decoders or the external JXL one.

[Quackdoc]

Doing file extension isn't the most reliable as some users like to mess with file extensions, some apps might use their own file extensions etc.

what about doing bufread instead? There is a better way of handling bufread instead of using fill_buf, limiting the amount of bytes needed for the buffer for image probing will be faster then this, but the current hit is not bad, and I can't think of the best way to do that ATM.

  let srcfile = std::fs::File::open(source)
    .ok().expect("could not open source file");
    let mut srcbuf = BufReader::new(srcfile);

    let source: DynamicImage = match image::guess_format(&mut srcbuf.fill_buf().unwrap()) {
        Ok(image) => {
            image::load(srcbuf, image).unwrap()
        }
        Err(decode_error) => {
            println!("{}",decode_error);
            println!("trying jxl-oxide");
            match jxl_oxide::integration::JxlDecoder::new(srcbuf) {
                Ok(decoder) => match image::DynamicImage::from_decoder(decoder) {
                    Ok(img) => img,
                    Err(e) => panic!("failed to decode source jxl: {}", e),
                },
                Err(e) => panic!("Failed to open the source file: {}", e),
            }
        }
    };

the difference is

AFTER:
time ssimulacra2_rs image Pahtra3-Edited.png Pahtra3-Edited.png
Score: 100.00000000
ssimulacra2_rs image Pahtra3-Edited.png Pahtra3-Edited.png   2.07s  user 0.48s system 99% cpu 2.573 total
avg shared (code):         0 KB
avg unshared (data/stack): 0 KB
total (sum):               0 KB
max memory:                624 MB

BEFORE:
ssimulacra2_rs image Pahtra3-Edited.png Pahtra3-Edited.png
Score: 100.00000000
~/code/ssimu2/ssimulacra2_bin/target/release/ssimulacra2_rs image     2.05s  user 0.49s system 99% cpu 2.562 total
avg shared (code):         0 KB
avg unshared (data/stack): 0 KB
total (sum):               0 KB
max memory:                623 MB

[Quackdoc]

I don't think I'll keep the match statement since adding more codecs in the future like this won't be great. I still need to think on the best way to keep this sleek while keeping jxl-oxide optional.

[FreezyLemon]

If we want to go by file content, I don't think there's a simple way to avoid re-opening the file anyways, so that is probably fine. Keeping it sleek isn't that important as long as it works well.

BTW: Is there a reason for doing File::open(path).ok().expect("...")? The .ok() is unnecessary, right?