Create function for deleting an inventory entry, add to RESTful endpoint.

[bleehu]

The ask for this ticket is to add a function that deletes a given inventory entry if an HTTP DELETE is passed to the RESTful endpoint with the pk_id of the inventory entry. Don't forget to check the permissions of the user that sent the API call!

[bleehu]

Deleting an item should be as easy as setting the SQL entry's deleted_at field to the now() SQL function.