Split TaskManager into

- DependencyManager spawns dependencies if necessary
- WorkflowManager processes running workflows to see if a new job is
  ready to spawn
- TaskManager starts tasks if unblocked and has execution capacity

awx/main/scheduler/tasks.py

@@ -2,7 +2,7 @@
 import logging
 
 # AWX
-from awx.main.scheduler import TaskManager
+from awx.main.scheduler import TaskManager, DependencyManager, WorkflowManager
 from awx.main.dispatch.publish import task
 from awx.main.dispatch import get_local_queuename
 
@@ -10,6 +10,21 @@ logger = logging.getLogger('awx.main.scheduler')
 
 
 @task(queue=get_local_queuename)
-def run_task_manager():
-    logger.debug("Running task manager.")
+def task_manager():
     TaskManager().schedule()
+
+
+@task(queue=get_local_queuename)
+def dependency_manager():
+    DependencyManager().schedule()
+
+
+@task(queue=get_local_queuename)
+def workflow_manager():
+    WorkflowManager().schedule()
+
+
+def run_task_manager():
+    task_manager()
+    dependency_manager()
+    workflow_manager()