SDRP — Unregister Operation Issues

Problem

The domain manager and device manager unregister operations take in an object reference, which cannot be used directly for determining what component to unregister since one cannot compare on object references, so a callback is needed to get the identifier for unregistering service thus being inefficient.

Proposed Solution: Replace the unregistering operations and remove device parameters with an unregistering identifier parameter of string type. This change affects CompositeDevice, DeviceManagerRegistration and ServiceRegistration interfaces.