Show when a node is deprecated on the node page

[kevinschaper]

One piece that we left out of #421 is explicitly showing when a node is deprecated/obsolete. We should add something fairly clear in the UI on the node pages to address that. (if only the blink tag still worked)

This is something that we probably could put into an app-only patch of the November release, but otherwise let's make sure it's in place for December.