Support for "shared" semantics in ResourceService

In current design allocating resource, allocates all its child's resources as well.
In the Optical Use Case, we have Och Port Resource with ODU-TS as its child Resources.
Och Port is allocated by OpticalConnectivityIntents, while the ODU-TS are allocated by the CircuitIntent.
So, the exclusive mode of allocation (allocate resource and all its child resources), should not be the default behavior. Need to consider adding a parameter to the allocate() API which will specify whether Only the specified resource should be allocated or the resource and all its child resources.