[Feature request] Provide a DecorationImage alternative

[PureTryOut]

It would be nice if we could use Avif images for a DecorationImage. I realize I can just provide a MemoryAvifImage to it but we're already providing https://pub.dev/packages/cached_network_image to it to cache our network images rather than constantly retrieving them every time we show the widget. I can use that package in combination with a regular AvifImage but in this case a DecorationImage is needed, but I'd still like it to be an Avif image and cache it :wink: