fix: deletion of entity objects

In GenericEntitiesDeleteView, override get_queryset() method
instead of referencing a specific (parent) model to get at the
object-to-be-deleted.

Closes #485

apis_core/apis_entities/edit_generic.py

@@ -165,13 +165,13 @@ def post(self, request, *args, **kwargs):
 
 @method_decorator(login_required, name="dispatch")
 class GenericEntitiesDeleteView(EntityInstanceMixin, DeleteView):
-    # model = ContentType.objects.get(
-    #     app_label='apis_entities', model='tempentityclass').model_class()
-    model = importlib.import_module("apis_core.apis_entities.models").TempEntityClass
     template_name = getattr(
         settings, "APIS_DELETE_VIEW_TEMPLATE", "confirm_delete.html"
     )
 
+    def get_queryset(self):
+        return self.entity_model.objects.all()
+
     def dispatch(self, request, *args, **kwargs):
         self.success_url = reverse(
             "apis_core:apis_entities:generic_entities_list",