Short: Implement plugin FroshPlatformThumbnailProcessor into the core

Longer: Add the ability to define a pattern for thumbnails to be used instead of creating or requesting thumbnails from storage. Additionally, shopware could host a service to convert images on the fly, f.e. see imgproxy.net - maybe just with nicer links. Just add a caching before that and win.

Advantages: Any shop owner has webp/avif-images with the best compression and suitable sizes without wasting storages.