Retraction wizard - Step 3: Destruction

[olle]

Retraction wizard steps:

1. [Ticket #526] Marking extracts for retraction, produce lists and protocols to simplify finding these in the lab or external storage.
2. [Tickets #723, #769] Follow-up of step 1, where a web form is presented for a selected retraction object, allowing dates to be entered when different sub-steps are finished. When all sub-steps are marked to have been finished, the items are marked to be ready for deletion/destruction.

This ticket is concerned with the final step, where a retraction object ready for deletion/destruction is selected, after which a list of items to be deleted, and data to be be kept, is displayed. After approval, the items listed for deletion will be deleted from the database, copies of the case and biosource items will be created, after which the original case and biosource items will also be deleted (biosource here refers to a "patient" item of type Retract or RetroNo). Copies of the last two items are used, in order not to have references to log data for changes of the item data. The reason for keeping copies of the case and biosource items, is to prevent their SCAN-B id values to be reused by new items.