Bette Midler is such an incredible self-creation"an artist like no other"that finding roles that can harness her enormous energy while allowing room for her wit and her extraordinary skill as a balladeer must have long been a nightmare for her agents. Early in her now more than fifty-year career, Midler did happen upon a part that tapped into her many talents. In 1979, she starred in "The Rose," a fictional film port…