This PR also fixes up various broken links, etc., bur primarily deletes the Procedures directory (as all of its contents are now in the planetarypy.github.io repo and served via planetarypy.org) and the package listing from the README (which we always knew was temporary).
This PR completes the move of "Affiliated Packages" being listed and managed from the planetarypy.github.io repo instead of this one.
The canonical Affiliated Package listing is now at https://github.com/planetarypy/planetarypy.github.io/blob/src/data/registry.json
This PR also fixes up various broken links, etc., bur primarily deletes the Procedures directory (as all of its contents are now in the planetarypy.github.io repo and served via planetarypy.org) and the package listing from the README (which we always knew was temporary).