SHARM EL-SHEIKH, Egypt (Reuters) - Arab leaders meeting in Egypt said on Saturday they opposed an attack on Iraq as a threat to Arab national security and declared their countries would not take part in any war. The United Arab Emirates proposed that Iraqi President Saddam Hussein and top aides should step down and go into exile -- the first time an Arab state has made an official call of this kind -- but the summit declined to discuss the idea. Washington, threatening to attack Iraq for not ridding itself voluntarily of alleged weapons of mass destruction, has said removing...