start deprecating the whole properties thing for datadomain

since DD is no longer used in the Modeler, and we have a DI provider to create it in runtime,
storing and parsing properties just doesn't make sense here

git-svn-id: https://svn.apache.org/repos/asf/cayenne/main/trunk@1538397 13f79535-47bb-0310-9956-ffa450edef68