add JPEG XL support via pillow-jpegxl-plugin

[BPplays]

this PR adds JPEG XL support via a pillow plugin pillow-jpegxl-plugin.
I've tested on JPEG XL images made with libjxl cjxl and it seems to work fine
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this closes #333

[eivl]

I dont know the image format, but the implementation looks correct.
Just keep in mind that pillow plugins and pillow itself needs to be lifted to newer versions when 3.13 support is in the works.

[EugeneVert]

Just as a note, jxlpy may be a better choice, as it uses direct bindings to libjxl and has an MIT license. At the same time, the pillow-jpegxl-plugin seems to be doing a python->rust->libjxl binding through jpegxl-rs, which has GPL-3.0 license.
But keeping in mind that TagStudio itself has a GPL-3.0 licence, both jxlpy and pillow-jpegxl-plugin both seem to be suitable

[BPplays]

@EugeneVert i went with pillow-jpegxl-plugin because jxlpy claims: 'This project is still in alpha stages and needs testing. It may contain bugs!'. and it says support status for the pillow plugin is 'Partial' so i don't know how well it works

[CyanVoxel]

From what I understand, pillow-jpegxl-plugin presents itself as having an MIT license despite using bindings from jpegxl-rs which is under GPL-3: meaning that (as far as I understand license-wise) that pillow-jpegxl-plugin can't really be distributed under MIT.

Furthermore, jxlpy which also presents itself as MIT and uses bindings from libjxl which in turn is licensed under BSD-3: an equally incompatible license with MIT.

What does this mean for this project though? Well since TagStudio uses GPL-3, it's compatible with GPL-3 and BSD-3 regardless. It's just worth it to note that these libraries may update their licenses at some point to comply with the libraries they use, and that neither may truly be "MIT".

[CyanVoxel]

Unfortunately I'm having trouble sourcing jxl files to test, and can't verify that they're appearing how they should. Since chrome-based browsers don't support jxl and most if not all of my image viewing and editing software has limited support if any at all, I can't tell if any of these files are appearing as they're intended to. I've found a discrepancy in one of them but I don't know if it's an error on the side of my image viewer or on the PIL plugin (or both). If you have some jxl files along with a reference overview of how they're supposed to appear, that would be greatly appreciated.

[BPplays]

@CyanVoxel
here is a zip with some images inside: jxl, webp, and png of the same image
https://github.com/BPplays/images/raw/main/issues/jxl_ts/jxldem/👍.zip

there are also jpeg xls on https://jpegxl.info/test-page/.
floorp browser and qview support them out of the box pretty well, floorp seems to have fixed the issues with firefox's experimental support.

also can you send me the image you found a discrepancy in with to test it.

[floogulinc]

The author of jxlpy has a PR adding JPEG-XL support to Pillow itself that hopefully will be merged at some point. We're waiting for that for hydrus as at least last time I tried using either of these plugins they weren't really working, though perhaps that has changed seeing as it seems to be working somewhat here.

python-pillow/Pillow#7848

[BPplays]

@floogulinc the plugin i used for this PR seems to work fine with images i converted using cjxl from libjxl,
i wanted to use a plugin instead of waiting for python-pillow/Pillow/pull/7848 because the PR doesn't seem very active