This is a follow-up to https://github.com/backdrop/backdrop-issues/issues/2632
The goal is to get rid of the "Manage file display" page entirely. We should move the settings that are currently on that page under a "configure" link on the
File row on the usual "manage displays" page. A good example of what this would look like can be found on any other fieldable entity.
Example of configure link (closed):
Example of configure link (open):
Current settings on the "Manage file display" page:
Destination for these settings: