ActualLRP organized by embedded structs

* ActualLRPKey contains ProcessGuid, Index, and Domain and is the primary key
  for an ActualLRP (with the Domain denormalized from its DesiredLRP)
* ActualLRPContainerKey contains InstanceGuid and CellID and denotes which
  cell owns the claimed or running container
* ActualLRPNetInfo contains the Host and Ports
* Remove NewActualLRP constructor in favor of constructors for these types

* It is no longer valid for an Unclaimed ActualLRP to have an InstanceGuid set
* LRPStartAuction no longer requires an InstanceGuid, as that should no longer
  be set for an Unclaimed ActualLRP

[#84359170]

Signed-off-by: Ashvin Agrawal <ashvin@pivotal.io>
ActualLRPKey and ActualLRPContainerKey validate

[#84359170]

Signed-off-by: Ashvin Agrawal <ashvin@pivotal.io>