Add deposit-admin tab to the admin interface

After viewing the very cool admin interface for save code now, we decided that adding a tab for the deposits instead of creating a view on the deposit platform is the best way to go.

This way the access to the list of deposits is only possible with admin login.

Also it prevents the creation of multiple places to view user activity. And very importantly, it prevents code duplication !!

Here is a suggestion for the the table's columns:

swh-id can be omitted with only a link to the archive object when status is 'done'.

Migrated from T1170 (view on Phabricator)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information