Add setting for configuring optional URL prefix for /api (#14939)

* Add setting for configuring optional URL prefix for /api

Add OPTIONAL_API_URLPATTERN_PREFIX setting

examples:
- if set to `''` (empty string) API pattern will be `/api`
- if set to 'controller' API pattern will be `/api` AND `/api/controller`

awx/urls.py

@@ -2,7 +2,7 @@
 # All Rights Reserved.
 
 from django.conf import settings
-from django.urls import re_path, include
+from django.urls import path, re_path, include
 
 from ansible_base.resource_registry.urls import urlpatterns as resource_api_urls
 
@@ -12,7 +12,15 @@ from awx.main.views import handle_400, handle_403, handle_404, handle_500, handl
 urlpatterns = [
     re_path(r'', include('awx.ui.urls', namespace='ui')),
     re_path(r'^ui_next/.*', include('awx.ui_next.urls', namespace='ui_next')),
-    re_path(r'^api/', include('awx.api.urls', namespace='api')),
+    path('api/', include('awx.api.urls', namespace='api')),
+]
+
+if settings.OPTIONAL_API_URLPATTERN_PREFIX:
+    urlpatterns += [
+        path(f'api/{settings.OPTIONAL_API_URLPATTERN_PREFIX}/', include('awx.api.urls')),
+    ]
+
+urlpatterns += [
     re_path(r'^api/v2/', include(resource_api_urls)),
     re_path(r'^sso/', include('awx.sso.urls', namespace='sso')),
     re_path(r'^sso/', include('social_django.urls', namespace='social')),