Control the visibility and use of hop node Instances

- the list, detail, and health check API views should not include them
- the Instance-InstanceGroup association views should not allow them
  to be changed
- the ping view excludes them
- list_instances management command excludes them
- Instance.set_capacity_value sets hop nodes to 0 capacity
- TaskManager will exclude them from the nodes available for job execution
- TaskManager.reap_jobs_from_orphaned_instances will consider hop nodes
  to be an orphaned instance
- The apply_cluster_membership_policies task will not manipulate hop nodes
- get_broadcast_hosts will ignore hop nodes
- active_count also will ignore hop nodes

awx/main/managers.py

@@ -188,7 +188,7 @@ class InstanceManager(models.Manager):
 
     def active_count(self):
         """Return count of active Tower nodes for licensing."""
-        return self.all().count()
+        return self.exclude(node_type='hop').count()
 
 
 class InstanceGroupManager(models.Manager):