add support for building swagger/OpenAPI JSON

to build, run `make swagger`; a file named `swagger.json` will be
written to the current working directory

awx/api/urls/urls.py

@@ -2,7 +2,9 @@
 # All Rights Reserved.
 
 from __future__ import absolute_import, unicode_literals
+from django.conf import settings
 from django.conf.urls import include, url
+from awx.api.swagger import SwaggerSchemaView
 
 from awx.api.views import (
     ApiRootView,
@@ -123,5 +125,9 @@ app_name = 'api'
 urlpatterns = [
     url(r'^$', ApiRootView.as_view(), name='api_root_view'),
     url(r'^(?P<version>(v2))/', include(v2_urls)),
-    url(r'^(?P<version>(v1|v2))/', include(v1_urls))
+    url(r'^(?P<version>(v1|v2))/', include(v1_urls)),
 ]
+if settings.SETTINGS_MODULE == 'awx.settings.development':
+    urlpatterns += [
+        url(r'^swagger/$', SwaggerSchemaView.as_view(), name='swagger_view'),
+    ]