This PR is offloading some of the partitioning logic to the partitioning
manager, effectively changing
the partitioning interface. Rather than always relying on the
PartitionFieldExtention data structure to
convey partition IDs, we make it implementation defined by introducing
the partitioning manager abstraction.
We want user to be able to extract the partitionId more flexibly and
this requires using a SimObject.
Users can extend the PartitioningManager, overriding the
readPacketPartitionId, therefore providing their
own mean of injecting/extracting partitioning data from a packet
3af15a535e