Add WP CLI scripting for the replacement of old image URLs

Before merging, it would be cool if this new WP CLI command did this for us:

[ ] List images by domain and path
[ ] Sideload images into WordPress
[ ] Replace instances of sideloaded image with new URL
[ ] Attach images that are used once to their parent post

`wp newsfix list_images` currently works to display image domain and path statistics in post content.