Continue to support Pacemaker for 2.x topologies

Instead determining whether to use RPC heartbeats or not on topology storm version, use the setup to identify Supervisor/Pacemaker is being used to route heartbeats.

For large clusters, where pacemaker is needed in many circumstances where supervisor daemons are getting overloaded or Supervisor daemon is not available and way to many workers reach out to nimbus. This is showing high load on nimbus.