By Omer Berberoglu KYIV (Reuters) -Kyiv mayor and former heavyweight boxing champion Vitali Klitschko said on Friday that he believed there were nearly 2 million people still left in the city, which is being squeezed by advancing Russian forces on several fronts. He said the Ukrainian capital, normally with a population of 3.5 million, had enough vital provisions to last a couple of weeks, and that supply lines in and out remained open for now. His brother Wladimir, also a heavyweight boxing star, added in a joint interview that some men and women who had accompanied their families to the rela…