Use variables to set rabbitmq host and port

installer/roles/local_docker/templates/credentials.py.j2

@@ -13,9 +13,9 @@ DATABASES = {
 BROKER_URL = 'amqp://{}:{}@{}:{}/{}'.format(
     "{{ rabbitmq_user }}",
     "{{ rabbitmq_password }}",
-    "{{ rabbitmq_host }}",
+    "{{ rabbitmq_host | default('rabbitmq')}}",
     "{{ rabbitmq_port }}",
-    "awx")
+    "{{ rabbitmq_default_vhost }}")
 
 CHANNEL_LAYERS = {
     'default': {'BACKEND': 'asgi_amqp.AMQPChannelLayer',