When Thomas H. Geoghegan was first inspired to sit down and write his play about Thomas Jefferson, Donald Trump wasn’t a frontrunner in the 2016 presidential election and “Hamilton: An American Musical” hadn’t premiered yet.But “Monticello” — and its questions about the ideals of freedom and equality in a country that enslaved people based on the color of their skin — appears to be timelier than ever, Geoghegan, a shareholder at Despres Schwartz and Geoghegan Ltd …