“I’m in my infancy as a rock star,” Tony-nominated Broadway vet Matthew Morrison quipped after his August 1 concert at the Beacon Theatre, linked to the release his self-titled pop album. Backed by a rocking five-piece band and a trio of backup singers, the Glee star sang a mix of original songs and covers spanning five decades, from “The Lady Is a Tramp” and “Great Balls of Fire” to “Mrs. Robinson” and “Gold Digger.” There was even a special treat for theater fans: a West Side Story medley accompanied by bongos, inspired by Sammy Davis Jr.“It was very personal