BOSTON — The defense team representing the Boston Marathon bombing suspect got a major boost Monday with the addition of Judy Clarke, a San Diego lawyer who has managed to get life sentences instead of the death penalty for several high-profile clients, including the Unabomber and the gunman in the rampage that injured former Arizona Rep. Gabrielle Giffords. Clarke’s appointment was approved Monday by U.S. Magistrate Judge Marianne Bowler....