U.S. Ambassador to the United Nations Nikki Haley is stepping down at the end of this year, President Donald Trump said Tuesday, in the latest exit from the president's national security team."She's done a fantastic job, but we've done a fantastic job together," Trump told reporters as Haley sat next to him in the Oval Office. "We're all happy for you in one way, but we hate to lose you."The president said he will select a successor to Haley in the next two to three weeks, adding that a number of people want to do her job such as Goldman Sachs executive and former deputy national security a…READ FULL ARTICLE