Add support for product edit page

[erikhansen]

This is likely outside the scope of this extension, but it would be great to have an extension that could satisfy the following user story:

As a merchant editing a product in the admin, I would like to be able to see if product attributes are overridden at a more specific scope.

I know I have M2 merchants that would appreciate this functionality. Feel free to close this issue if you don't think this functionality belongs in this extension. If you changed the name of this extension to "ScopeHints", there would be nothing in the name of the extension that would prevent it from covering both product attributes and config fields.