Support webp image style generation via imageoptimize_webp module

Here's an updated patch for 3.3. Should this issue still be postponed? Is there a usable solution currently aside from this patch? Any further clarity on what the solution should be going forward would be helpful to all.

✨ Split ImageStyle into the config entity and a separate event-based image processing service Needs work is probably the real solution going forward.

I'm almost inclined to mark this and the associated issue won't-fix.

As a streamWrapper we shouldn't be too tied to site structure and should be able to be agnostic. I'm not inclined to be supporting multiple ad-hoc solutions for each 3rd party module. I'm willing to make changes to support a new standardized API, so if ✨ Split ImageStyle into the config entity and a separate event-based image processing service Needs work were either merged to core, or converted into a contrib module with the webp modules and variants adopting it I would look into it.

Closing as won't fix as this really needs a standardized API meaning Core, or a contrib module needs to provide this first and we will want a new issue to implement the API when it exists.

In my opinion ✨ Split ImageStyle into the config entity and a separate event-based image processing service Needs work is the best issue to support for a resolution to this request.