A query optimization in bda.views.catalogue

We only need to fetch shows identifiers here:

    FOO.filter(BAR__in=shows)

which can be done using the `values_list` method

bda/views.py

@@ -672,15 +672,16 @@ def catalogue(request, request_type):
             return HttpResponseBadRequest(
                 "Bad format: int expected for `id`"
             )
+        shows = tirage.spectacle_set.values_list("id", flat=True)
         categories = list(
             CategorieSpectacle.objects
-            .filter(spectacle__in=tirage.spectacle_set.all())
+            .filter(spectacle__in=shows)
             .distinct()
             .values('id', 'name')
         )
         locations = list(
             Salle.objects
-            .filter(spectacle__in=tirage.spectacle_set.all())
+            .filter(spectacle__in=shows)
             .distinct()
             .values('id', 'name')
         )