Deleted Bitstream tombstone page

[ybnd]

Is your feature request related to a problem? Please describe.

Bitstream records with deleted=true always lead to /404 the DSpace UI, even for administrators.
This means we cannot display original versions of Bitstreams that have been replaced.

Describe the solution you'd like

When a Bitstream is deleted, administrators should be able to view its /bitstreams/.../edit

• The page should clearly specify that this Bitstream has been deleted and is no longer accessible, and the form should be disabled
• We shouldn't include deleted Bitstreams on /items/.../edit/bitstreams, as they would be linked from other edit Bitstream pages

Additional information

Relevant to #4368

[lgeggleston]

Hi @ybnd, thanks for submitting this ticket! Marking it for discussion for now, just to gather extra opinions and make sure it doesn't conflict with other recent changes, for example this one ensuring the API returns 404 for deleted bitstreams: (DSpace/DSpace#11655).