Support for AUTO_AVIF

[MuuKojima]

I noticed that there is a setting for "AUTO_WEBP", but it seems there isn't one for "AUTO_AVIF".
Are there any plans to implement it?
If it's okay, I would like to create a PR for it.

[simonkrol]

Hi @MuuKojima,
We don't currently have plans to implement it, we noticed during testing that converting to AVIF in Sharp can be quite a slow operation, and would sometimes cause timeouts to occur (Sharp issue). With that, we didn't see a huge amount of value in adding auto AVIF functionality.

If this would still be something you would use despite the performance hits, please let us know.
Simon

[MuuKojima]

@simonkrol
I see, there were several reasons for that.
Thank you.