This PR creates a new directory called `featured-items` which includes both blocks.
All the shared code lives at the top level of that directory.
Individual blocks still have their own directories, with their `block.json` and all other relevant configuration.
All the functionalities have been refactored out into their own files, accepting configuration when relevant, but mostly de-duplicating all the code.
Styles have also been refactored using mixins and extends and they mostly live in one place.