GREENBELT, Md. — President Trump’s former national security adviser John Bolton pleaded guilty Friday to a single count of hoarding national defense information while working in the White House, leaving the 77-year-old facing up to five years in federal prison. Bolton, an Iran hawk and former US ambassador to the United Nations, copped to the charge during a brief hearing in federal court just outside Washington, responding to US District Judge Theodore Chuang’s inquiry about whether he was