#249 Created as modified

* fills modified attribute on new entries with created value automatically
* adds default ordering by last modified on table overviews

api/utils/serializer/v1/ecoaccount.py

@@ -103,6 +103,7 @@ class EcoAccountAPISerializerV1(AbstractModelAPISerializerV1,
         obj.legal = Legal()
         created = create_action
         obj.created = created
+        obj.modified = created
         obj.geometry = geometry
         return obj