Create internal drivers for each object that will use dictionaries instead of objects, and will use a generic fail/success notifiers. The LBaaS nsx-v/v3 drivers will translate the objects to dictionaries and use the LBaaS callbacks for successful_completion and failed_completion. Later we can add drivers for Octavia that will use the same internal drivers. Change-Id: I5f99f979bd5333ccfc781217379d217d611cb015