Add home_page data element

[david-a-wheeler]

Identifying projects can be hard, since names aren't globally unique.

One solution, used by the CII Best Practices badge, is to add a "home_page" URL (in addition to a repo URL) along with version identifiers to identify a project. Since DNS names are globally unique, and home page URLs are generally used by projects anyway, using a home page to identify OSS components or software that uses them. This increases the likelihood of identifying the components.