Universal. Portable. Preventive. Those three concepts were the theme of the preview New Haven’s John DeStefano offered Thursday of a sweeping health care plan he plans to thrust into this year’s gubernatorial campaign.Health care has already become a central issue in this year’s race. Stamford Mayor Dan Malloy, the other Democrat seeking to become governor, unveiled his own health care plan last week. It called for expanding HUSKY so that all Connecticut children have health insurance. DeStefano claimed his plan would go far further than Malloy’s, promising coverage not just to kids, but to their parents and other adults.