By Max Hunder KYIV (Reuters) -Russian forces have destroyed the last bridge to Ukraine’s eastern frontline city of Sievierodonetsk, trapping any remaining civilians there and making it impossible to get in humanitarian supplies, the region’s governor said on Monday. Governor Serhiy Gaidai said some limited military access remained however to the devastasted city that has become a key battleground for Ukraine as it tries to halt Russia’s advance across its industrial Donbas heartland. “It is now fully impossible unfortunately to drive into the city, to deliver something to the city. Evacuation …