Mike Barnicle, the hard-hitting veteran journalist whose lively commentary has engaged and informed New Englanders for almost 30 years, is returning to the Boston newspaper scene as a columnist for the Boston Herald, Publisher Patrick J. Purcell announced today. Purcell said that Barnicle, who has been a columnist for the New York Daily News for the past five years, serves as a commentator on national and local news programs and hosts his own radio talk show, will join the Boston Herald as a featured columnist every Tuesday and Thursday, beginning tomorrow. ``It's not every day that you have an opportunity...