Add a "Dive details" widget to the print dialog

Ok, so the widget doesn't actually *do* anything, but this is where you
would add dive printing settings for things like "print list" vs "print
profiles" etc.

Printing just a dense dive table (no profiles etc) is being discussed on
the list, maybe starting the scaffolding will inspire somebody to do
something about it ...

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>