The romantic tearjerker “The Notebook” lands on Broadway in awkward musical theater form this spring. It is intent now on making a live audience openly weep by employing massive doses of schlocky sentimentality without the aid of Ryan Gosling. The bombastic musical that opened Thursday at the Gerald Schoenfeld Theatre is about a love for the ages but has understated songs by Ingrid Michaelson. This adaptation from a Nicholas Sparks novel is the love story of poor boy