ALBANY — Megabuilder and late-blooming TV star Donald Trump yesterday flatly ruled out running for governor this year — but hinted he may go for president in 2008. Trump, in a phone call to The Post from his oceanside Palm Beach estate, Mar-a-Lago, declared, "I'm not going to run for governor because I'm having too much fun doing what I'm doing now. "I'm the largest builder in New York, I'm building things all over the country, I have one of the top shows on television. It's a little hard to leave all of that." Trump, a Republican, said he had...