(This story contains graphic descriptions) By Simon Gardner BUCHA, Ukraine (Reuters) – Sobbing uncontrollably, Serhii Lahovskyi nuzzles against the shrouded corpse of his closest childhood friend, who disappeared when Russian troops occupied the Ukrainian town of Bucha near Kyiv and was found shot through the head and dumped in a stairwell. The labourer’s eyes cloudy and half open, black and crimson streaks of blood caked on his face and snaking down to his lips from an exit wound that cracked his skull, Igor Litvinenko had been shot through the mouth at very close range. He was found by local…