Apply capacity algorithm changes

* This also adds fields to the instance view for tracking cpu and
  memory usage as well as information on what the capacity ranges are
* Also adds a flag for enabling/disabling instances which removes them
  from all queues and has them stop processing new work
* The capacity is now based almost exclusively on some value relative
  to forks
* capacity_adjustment allows you to commit an instance to a certain
  amount of forks, cpu focused or memory focused
* Each job run adds a single fork overhead (that's the reasoning
  behind the +1)

awx/main/tests/unit/utils/test_ha.py

@@ -60,6 +60,7 @@ class TestAddRemoveCeleryWorkerQueues():
                                                    static_queues, _worker_queues, 
                                                    groups, hostname,
                                                    added_expected, removed_expected):
+        added_expected.append('tower_instance_router')
         instance = instance_generator(groups=groups, hostname=hostname)
         worker_queues = worker_queues_generator(_worker_queues)
         with mock.patch('awx.main.utils.ha.settings.AWX_CELERY_QUEUES_STATIC', static_queues):