Add new capabilities to the capabilities home page and navigation bar

[nathenharvey]

After all of the new capabilities are ready:

• Add to capabilities home page (/capabilities)
• Add to capabilities right-nav

[nathenharvey]

The new capabilities don't currently show up in the search index. This may be because the primary way to navigate to them currently is via the interactive model.

[nathenharvey]

Fixed with #1255