replace celery task decorators with a kombu-based publisher

this commit implements the bulk of `awx-manage run_dispatcher`, a new
command that binds to RabbitMQ via kombu and balances messages across
a pool of workers that are similar to celeryd workers in spirit.
Specifically, this includes:

- a new decorator, `awx.main.dispatch.task`, which can be used to
  decorate functions or classes so that they can be designated as
  "Tasks"
- support for fanout/broadcast tasks (at this point in time, only
  `conf.Setting` memcached flushes use this functionality)
- support for job reaping
- support for success/failure hooks for job runs (i.e.,
  `handle_work_success` and `handle_work_error`)
- support for auto scaling worker pool that scale processes up and down
  on demand
- minimal support for RPC, such as status checks and pool recycle/reload

awx/settings/production.py

@@ -54,21 +54,13 @@ AWX_ISOLATED_USERNAME = 'awx'
 
 LOGGING['handlers']['tower_warnings']['filename'] = '/var/log/tower/tower.log'
 LOGGING['handlers']['callback_receiver']['filename'] = '/var/log/tower/callback_receiver.log'
+LOGGING['handlers']['dispatcher']['filename'] = '/var/log/tower/dispatcher.log'
 LOGGING['handlers']['task_system']['filename'] = '/var/log/tower/task_system.log'
 LOGGING['handlers']['fact_receiver']['filename'] = '/var/log/tower/fact_receiver.log'
 LOGGING['handlers']['management_playbooks']['filename'] = '/var/log/tower/management_playbooks.log'
 LOGGING['handlers']['system_tracking_migrations']['filename'] = '/var/log/tower/tower_system_tracking_migrations.log'
 LOGGING['handlers']['rbac_migrations']['filename'] = '/var/log/tower/tower_rbac_migrations.log'
 
-# Supervisor service name dictionary used for programatic restart
-SERVICE_NAME_DICT = {
-    "beat": "awx-celery-beat",
-    "celery": "awx-celery",
-    "callback": "awx-callback-receiver",
-    "channels": "awx-channels-worker",
-    "uwsgi": "awx-uwsgi",
-    "daphne": "awx-daphne"}
-
 # Store a snapshot of default settings at this point before loading any
 # customizable config files.
 DEFAULTS_SNAPSHOT = {}