After NBC's announcement that Jill Hennessy, Lauren Holly and Leslie Stefanson will play, respectively, "Jackie, Ethel Joan: The Women of Camelot," in the network's two-part, four-hour miniseries on the Kennedy wives in November, CBS is doing some Kennedy-name-dropping of its own. CBS will present Joanne Whalley in the leading role on its competing miniseries, "Jacqueline Kennedy Onassis: A Life," whose first installment is scheduled to air directly opposite NBC's, on Sunday, Nov. 5. The English-born Whalley, 35, was formerly married to actor Val Kilmer and is no stranger to miniseries. In 1994 she played Scarlett O'Hara on CBS's "Scarlett," the much-maligned (but much-watched) sequel to "Gone With the Wind."