Tommy Kearns is on his way to Australia to visit his new office in Melbourne via a stop-off to meet a customer in the Middle East. But he has time for a coffee in his office in Dublin the day before he flies out. The chief executive of Xtremepush is personable as he shows me around his offices, with the strongly-built frame of a hooker who played professionally for Connaught. On course for revenues of €40 million this year, his customer-engagement platform has invested millions in artificial intelligence (AI) and employs 170 people in London, Milton Keynes, Dublin, New York,…