As I got comfortable in my seat at the Bank of America Theatre and prepared to watch the pre-Broadway opening night performance of “Amazing Grace,” I couldn’t help but think back to those movies of my youth where a teenager, generally Mickey Rooney, to save an orphanage, would say, “Hey, kids, let’s put on a show!” That would be a daunting challenge today, when one considers the reality of how long it takes and how much it costs. So my thoughts went out immediately to former cop …