clubs: add bulk deletion on mailing lists

club/urls.py

@@ -70,11 +70,6 @@ urlpatterns = [
         MailingAutoGenerationView.as_view(),
         name="mailing_generate",
     ),
-    url(
-        r"^(?P<mailing_id>[0-9]+)/mailing/clean$",
-        MailingAutoCleanView.as_view(),
-        name="mailing_clean",
-    ),
     url(
         r"^(?P<mailing_id>[0-9]+)/mailing/delete$",
         MailingDeleteView.as_view(),