Perf: avoid unnecessary full-row fetches in batch permission assignment

set_permissions_for_objects now takes a model + pks instead of instances,
and identity filtering resolves straight to ids, so bulk-editing
permissions no longer materializes full Document/User/Group rows just to
read their pk/id. Row construction for bulk_create is also chunked to
bound peak memory for very large "apply to all" operations.

src/documents/tests/test_bulk_edit.py

@@ -636,7 +636,8 @@ class TestBulkEdit(DirectoriesMixin, TestCase):
         with self.assertRaises(Permission.DoesNotExist):
             set_permissions_for_objects(
                 {"not_a_real_action": {"users": [self.user1.id], "groups": []}},
-                [self.doc1],
+                Document,
+                [self.doc1.pk],
             )
 
     @mock.patch("documents.models.Document.delete")