One of every 84 people in Petersburg has HIV or AIDS. In Richmond, that number is one of every 91 people, and in Norfolk, it’s one of every 102 people. (The statewide rate is one in every 370 people.) These three urban areas are among the nation’s HIV and AIDS “hot spots,“ according to a group that yesterday launched a Web site that let users geographically map areas where the HIV and AIDS burden is high.