Add citation warning before permanent item deletion

[Paurikova2]

Problem

Currently, when an administrator deletes an item from the repository, there is no strong warning that:

• the item may already have been cited
• the item has (or had) a persistent identifier (Handle/DOI)
• deleting it may break scholarly references and external links

Proposed Improvement

Before permanent deletion of an item, display a confirmation dialog with a stronger warning, for example:
This item has a persistent identifier and may have already been cited. Deleting it may break references in scholarly literature and external systems. Are you sure you want to permanently delete this item?
Optional enhancements:

• Show the PID (Handle/DOI) in the dialog
• Recommend Withdraw instead of Delete when appropriate

[tdonohue]

@Paurikova2 : I agree with this overall, but I'd recommend a changing the text a bit simply because DSpace doesn't really require usage of permanent identifiers (though many do use them, not all sites sign up to use Handles or DOIs).

For instance maybe saying something like this:

Item deletion cannot be undone. Deletion will break any references or links to this item from external sites or systems. Are you sure you want to permanently delete this item?

I'd also recommend putting this text into the en.json5 translations file...that way it can be easily changed/customized for institutions who want to modify the warning text (or translate it).

Needs a volunteer to claim this ticket. (Let me know if you plan to work on it)

[Paurikova2]

@tdonohue I’m not planning to work on this for now. If that changes, I’ll let her know.