Show incoming links

[joepio]

Since Atomic Data is graph data, we should be able to show incoming links. Can be pretty useful:

• Show in which Classes a specific Property is Used
• Finding children of a resource

However, it'll also likely result in duplicate data on the screen, for example if a file has a bunch of attachments, because these attachments also have that file as parent. We might be able to prevent this by passing the rendered subjects to a parent component and use these for filtering, but that sounds pretty complicated to keep in sync. We could also simply accept the duplicate items and live our lives. Or, we could render the incoming resources in a separate view. Perhaps it should be a menu item, like the edit page.