improved handling of animated images

[BPplays]

I've changed the handling of animated images to include support for more types of animated images.
PR features:

• includes transcoding from an animated image type to webp or gif using pillow.
• only counts an image as animated if it has more then 1 frame
• checks what image types are support by qt and by pillow, as well as includes a list of known good types what pillow can encode with animation, and sorts available image types by quality

this PR also includes the changes from #344 so feel free to close that one if you prefer this one, though sadly that plugin doesn't seem to support decoding animated jxls

this also closes #333

[BPplays]

i added some code to test converting into animated webp before showing the image but it's sometimes causing crashing and i have no idea why, when it works for a small amount of time it seems to work.

[BPplays]

i think i might have fixed the crashing
it hasn't crashed once after testing a lot while developing it more, so im gonna call it fixed

[CyanVoxel]

Wanted to chime in here with the state of this PR and other relevant developments around the project.

#344 was at a sticking point regarding licenses, but is probably going to move forward with pillow-jpegxl-plugin assuming it functions correctly (I need to get my hands on some .jxl files).

In the meantime, I've unknowingly implemented some of changes here in #409 - mostly the animated image media type category and some code for loading GIFs into memory rather than streaming them from disk.

I would also suggest rebasing this to Alpha-v9.4, however there's likely due to be more than a few merge conflicts... Some of this is due to the changes mentioned above, and others are due to some git mishaps that happened in a recent update of Alpha-v9.4. But with the rest of the Alpha v9.4 milestone features out of the way, this should have a clear path on that branch now (outside of #344 presumably getting merged).

[BPplays]

@CyanVoxel i manually merged the work from the older version of this branch on to Alpha-v9.4
edit: here is a jxl

[eivl]

Are no tests affected by this PR after the gif changes? And is there a way to add missing tests?
I don't see anything that makes me think this would not work; I would also like a short description of how to test this live on my machine.

[BPplays]

Are no tests affected by this PR after the gif changes?

@eivl are there any tests for animated image handling?
i couldn't find any after a quick look in ./tagstudio/tests in the Alpha-v9.4 branch.

And is there a way to add missing tests?

probably