API webservices DELETE does not distinguish existing and non-existing items

[muhme]

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

Deleting an item (article, content category, banner, etc.) returns status 204 (NO CONTENT) for both existing and non-existing items. For API users, there is no single API call that can be used to securely delete an item. Two calls are required: first, the item must be retrieved to check whether it exists, and then it can be deleted.

Describe the solution you'd like

• Use distinct status codes, e.g. 404 (NOT EXIST) if we try to DELETE a non-existing item or
• Offer conditional deletes with sending additional header "If-Match: *"
  • If the resource exists → delete → 204
  • If it doesn’t exist → 412 Precondition Failed

Additional context

• See sample in [6.0] [webservices] cannot delete not trashed resource return 409 #45868
• Found [4.0] API Improvements #27569, but don't want to overload this old issue

[alikon]

please test #46161