Rename this repo to www.packageurl.org

[mjherzog]

We should rename this repository to www.packageurl.org to make the repo content more obvious.

Per https://docs.github.com/en/repositories/creating-and-managing-repositories/renaming-a-repository:

• GitHub automatically redirects most existing information (issues, wikis, stars, followers) to the new name. However, GitHub Pages sites using the github.io domain and calls to actions hosted by the repository may not redirect and may require manual updates.
• In addition to redirecting web traffic, all git clone, git fetch, or git push operations targeting the previous location will continue to function as if made on the new location. However, to reduce confusion, we strongly recommend updating any existing local clones to point to the new repository URL.
• If you plan to rename a repository that has a GitHub Pages site, we recommend using a custom domain for your site. This ensures that the site's URL isn't impacted by renaming the repository. For more information, see About custom domains and GitHub Pages.

So it seems that the impact will primarily affect any local clones and the github.io deployment.