replace flake8-import-order by isort

setup.cfg

@@ -8,3 +8,13 @@ application-import-names=mongoengine,tests
 # Limits the discovery to tests directory
 # avoids that it runs for instance the benchmark
 testpaths = tests
+
+[isort]
+known_first_party = mongoengine,tests
+default_section = THIRDPARTY
+multi_line_output = 3
+include_trailing_comma = True
+combine_as_imports = True
+line_length = 70
+ensure_newline_before_comments = 1
+order_by_type = 0