Rearrange the imports to meet the style guide

This also includes `from __future__ import absolute_import`
in every file so that the imports are consistent in Python 2 and 3.
The Python 2 tests fail without this.

tests/test_common/test_models/test_models.py

@@ -1,14 +1,21 @@
 # -*- coding: utf-8 -*-
 # SPDX-License-Identifier: MIT
-import pytest
+from __future__ import absolute_import
 
 from mock import patch
+import pytest
+
 from module_build_service import conf
 from module_build_service.common.models import ComponentBuild, ComponentBuildTrace, ModuleBuild
 from module_build_service.common.utils import load_mmd, mmd_to_str
 from module_build_service.scheduler.db_session import db_session
-from tests import init_data as init_data_contexts, clean_database, read_staged_data
-from tests import make_module_in_db, module_build_from_modulemd
+from tests import (
+    clean_database,
+    init_data as init_data_contexts,
+    make_module_in_db,
+    module_build_from_modulemd,
+    read_staged_data,
+)
 
 
 @pytest.mark.usefixtures("model_tests_init_data")