add skeletal Dataset class to disaggregator/utils folder
add skeletal Dataset class to disaggregator/utils folder


Former-commit-id: 24c329b0c97cceff0822c81cf8f3389cc5c79a30
Former-commit-id: fc9f1796bdbd311b19f3c83278689fb77259fb60
dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy,dssg/wikienergy