More than half a century after an adventurous teenager recorded “I Got You Babe” with her boyfriend Sonny Bono, the life and career of Cherilyn Sarkisian La Piere Bono Allman is being transformed into a lavish Broadway musical, The Cher Show. How can six decades of superstardom (with no end in sight) be compressed into one evening of theater? For starters, three charismatic actresses share the title role, narrating and commenting on the highs and lows of Cher’s oh-so-eventful