With its jazz-infused score by Paul Brill and silhouetted profiles of its detail-obsessed subject deep in thought, Dawn Porter’s engrossing four-part documentary depicts Kennedy as a blend of morally upright pop-culture icon and rich kid turned calculating political machine. “He’s two people … he’s a cop at heart,” says JFK, describing the fair-minded, uber-competitive runt of the litter who once worked for the communist-hating Joseph McCarthy but was also the brains behind his brother’s election to the Sen