Prevent a Developer / Designer from deleting a workflow

Add a permission level so that I can configure the Nintex environment to prevent the user with the Developer or Designer role from deleting a workflow.

This is really important because we want to give our normal business users a chance to develop workflows but we don't want these inexperienced users to accidentally delete a workflow that we have worked so long on. Once deleted, there is no getting it back. Only our admins should have delete permission.