Keep this as a separate commit as this isn't because the files have changed. The filenames have changed due to cache busting of PNG and Webp images.
See #8729
This commit pulls most of the image related logic into its own package, to make it easier to reason about and extend.
This is also a rewrite of the transformation logic used in Hugo Pipes, mostly to allow constructs like the one below:
{{ ($myimg | fingerprint ).Width }}
Fixes#5903Fixes#6234Fixes#6266
