“I Am Dale Earnhardt” digs deep beyond the legend to reveal the complex figure at the core of “The Intimidator.” He was an idol to millions, but a villain to others; a working man’s hero, but also a darling of Madison Avenue; a husband, father and friend, but also a solitary man who few really knew. His tragic death on the final lap of the 2001 Daytona 500 sent shock waves through the nation and immortalized him as one of the greatest stars NASCAR has ever known.