Add support for HEIF based images

[ynse01]

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Description

This PR is an attempt to start with #1320

Implemented decoding and encoding of images based on a HEIF (ISO/IEC 23008-12:2022) container. These include (amongst others): HEIC, HIF and AVIF.

Please note this PR does NOT add any new compression algorithm to ImageSharp. For now it will take a JPEG thumbnail as its pixel source.
Needless to say, much more work is needed after this PR to reach the goal. I'm try to help there also.

Please do let me know any comments, also on whether to support the HEIF file format in the first place.

[JimBobSquarePants]

Sounds like a plan !

The user community of AVIF encoders seems to be quite scattered, can't identify a dominant force there. Feel free to provide real-life images, so I can direct the support towards these.

For now, I plan for the following initial limitations to AV1 compression:

• 8 bit depth only
• Color pixels only
• Base Profile for now
• Square block sizes
• Split partition type only, to keep the blocks square
• DCT transform type only
• Limited selection of Prediction modes
• Limited subsampling options
• No filters
• No alpha
• No sequences / animation

I do plan to take both lossy and lossless into account from the start.

@JimBobSquarePants In the meantime, you could help my local workflow, by adding the relevant file extensions to GIT LFS in Shared-infrastructure please:

*.heic              filter=lfs diff=lfs merge=lfs -text
*.hif               filter=lfs diff=lfs merge=lfs -text
*.avif              filter=lfs diff=lfs merge=lfs -text

That all sounds great. Sorry about the delay, I've been very swamped.

If you use the following command in your fork you will get those changes.

git submodule foreach git pull origin main