José Mujica preparing a mate, the herbal drink offered in a hollowed calabash gourd, in his kitchen.Credit...Matilde Campodonico for The New York Times MONTEVIDEO, Uruguay — Some world leaders live in palaces. Some enjoy perks like having a discreet butler, a fleet of yachts or a wine cellar with vintage Champagnes. Then there is José Mujica, the former guerrilla who is Uruguay’s president. He liv