[UX] Reflect the status of the comment settings in the "Comment fields" and "Comment display" tabs and offer connect-the-dots links to enable them.

In the spirit of @jenlampton's "put things where users expect to find them" move, once #1262 is implemented, we should have it so that: 1. These tabs reflect the current setting. Something along the lines of "Comments are currently [closed|hidden] for the [content_type_name] content type.". 2. Either provide a link to the configure page and jump to the "Comment settings" tab (/admin/structure/types/manage/page#edit-comment) ...but then we'd need to figure a way to redirect the user back to the "Comment fields" or the "Comment display" tabs where they originally came from. 3. ...or open those settings (content type comment settings) in a modal so that the user does not have to leave the page they are at in the first place.