In a matter of months, former U.S. Special Envoy to Ukraine Keith Kellogg has swung through the infamous government-industry revolving door and is now advising a drone startup where he can profit directly from his recent diplomatic work and proximity to the government.Having only departed his diplomatic post in December, Kellogg was appointed Tuesday to the advisory board of Powerus, a company which counts Donald Trump’s sons Eric and Donald Jr. among its investors. It aims to leverage its “stro...