Fix DRF deprecation warnings (#23082)

Fix all deprecation warnings generated by Django REST Framework during the unit tests:

* ``The `base_name` argument is pending deprecation in favor of `basename`.`` (86 occurrences)
* `` `detail_route` is deprecated and will be removed in 3.10 in favor of `action`, which accepts a `detail` bool. Use `@action(detail=True)` instead.`` (18 occurrences)

lms/djangoapps/course_goals/urls.py

@@ -9,7 +9,7 @@ from rest_framework import routers
 from .views import CourseGoalViewSet
 
 router = routers.DefaultRouter()
-router.register(r'course_goals', CourseGoalViewSet, base_name='course_goal')
+router.register(r'course_goals', CourseGoalViewSet, basename='course_goal')
 
 urlpatterns = [
     url(r'^v0/', include((router.urls, "api"), namespace='v0')),

lms/djangoapps/discussion/notifier_api/urls.py

@@ -9,7 +9,7 @@ from rest_framework import routers
 from lms.djangoapps.discussion.notifier_api.views import NotifierUsersViewSet
 
 notifier_api_router = routers.DefaultRouter()
-notifier_api_router.register(r'users', NotifierUsersViewSet, base_name="notifier_users")
+notifier_api_router.register(r'users', NotifierUsersViewSet, basename="notifier_users")
 
 urlpatterns = [
     url(r'^v1/', include(notifier_api_router.urls)),

lms/djangoapps/discussion/rest_api/urls.py

@@ -20,8 +20,8 @@ from lms.djangoapps.discussion.rest_api.views import (
 )
 
 ROUTER = SimpleRouter()
-ROUTER.register("threads", ThreadViewSet, base_name="thread")
-ROUTER.register("comments", CommentViewSet, base_name="comment")
+ROUTER.register("threads", ThreadViewSet, basename="thread")
+ROUTER.register("comments", CommentViewSet, basename="comment")
 
 urlpatterns = [
     url(

lms/djangoapps/experiments/routers.py

@@ -23,7 +23,7 @@ class DefaultRouter(routers.DefaultRouter):
             initkwargs={'suffix': 'List'}
         ),
         # Dynamically generated list routes.
-        # Generated using @list_route decorator
+        # Generated using @action(detail=False) decorator
         # on methods of the viewset.
         DynamicRoute(
             url=r'^{prefix}/{lookup}{trailing_slash}$',
@@ -45,7 +45,7 @@ class DefaultRouter(routers.DefaultRouter):
             initkwargs={'suffix': 'Instance'}
         ),
         # Dynamically generated detail routes.
-        # Generated using @detail_route decorator on methods of the viewset.
+        # Generated using @action(detail=True) decorator on methods of the viewset.
         DynamicRoute(
             url=r'^{prefix}/{lookup}{trailing_slash}$',
             name='{basename}-detail',

lms/djangoapps/experiments/urls.py

@@ -8,8 +8,8 @@ from django.conf.urls import include, url
 from experiments import routers, views, views_custom
 
 router = routers.DefaultRouter()
-router.register(r'data', views.ExperimentDataViewSet, base_name='data')
-router.register(r'key-value', views.ExperimentKeyValueViewSet, base_name='key_value')
+router.register(r'data', views.ExperimentDataViewSet, basename='data')
+router.register(r'key-value', views.ExperimentKeyValueViewSet, basename='key_value')
 
 urlpatterns = [
     url(r'^v0/custom/REV-934/', views_custom.Rev934.as_view(), name='rev_934'),