swss: Add Voq counter support.

* Add m_voq_ids to SystemPortInfo to maintain the list of queue ids.
* Add two new tables COUNTERS_SYSTEM_PORT_NAME_MAP and
  COUNTERS_VOQ_NAME_MAP to enable queuestat to differentiate between
  Port Tx queues and Voqs.
* Add a new function initializeVoqs that retrieves the number of voqs
  for a system port and stores the voq object ids in m_voq_ids
* Add code to handle queue type SAI_QUEUE_TYPE_UNICAST_VOQ.
* Initialize voqs and populate COUNTERS_SYSTEM_PORT_NAME_MAP in
  addSystemPorts function.
* Update generateQueueMap to generate queue maps for both Txqs and Voq.
  For PHY ports in a voq system both Txqs and Voqs are instantiated. For
  Voqs of remote system port, only Voq counters are initialized.

Author: skbarista

orchagent/p4orch/tests/fake_portorch.cpp

@@ -582,7 +582,7 @@ bool PortsOrch::getQueueTypeAndIndex(sai_object_id_t queue_id, string &type, uin
     return true;
 }
 
-void PortsOrch::generateQueueMapPerPort(const Port &port)
+void PortsOrch::generateQueueMapPerPort(const Port &port, bool voq)
 {
 }