feat: add alto/image transformer

[kbond]

Adds an Alto\Image\Image transformer, and routes alto operations (OperationInterface) and Alto\Image\Transform objects to it so they can be passed to transform()/transformInPlace() directly, like Imagine and Intervention filters.

Draft until:

• alto/image cuts a stable release - the dev dep is dev-main today
• Keep shrink-on-load from moving the projection altophp/image#1 lands - without it imagick throws on any JPEG whose dimensions aren't DCT-aligned, so the transformer tests only pass under GD