In what may be a debut for the second half of a prodigious career, Steven Spielberg has created what is arguably the best American film ever made about the Holocaust: "Schindler's List," an extraordinary three hours and five minutes based on Thomas Keneally's 1982 historic novel. Not that Mr. Spielberg had that much competition. Despite the presence of Jews galore throughout Holly- wood, the film capital has a long-held aversion to de- picting the Holocaust. True, in 1960 came "Judgment at Nuremberg," which uncompromisingly indicted the Germans; in 1978 came "Sophie's Choice," an inquiry into the choiceless choices in the death camps. Both were decent, competent, well-intentioned, yet some- what pedestrian. "Schindler's List" rises above the mundane and the ordinary. It is explicit and graphic: Fountains of blood spurt from Jews' heads when Nazis shoot them at point-blank