By Ben Aris in Berlin Widely seen as a marriage of convenience, economic ties between Russia and China are rapidly deepening as the two countries are driven together by pressure from the West. As Nato foreign ministers gathered in Bucharest to show solidarity with Ukraine in its fight against Russia, top politicians and business leaders met for a Sino-Russian summit to pledge deeper cooperation and celebrate the rapidly expanding business ties, led by trade in energy. ‘China is becoming the largest consumer of Russian energy. This year, trade turnover in the energy sector has grown by 64% comp…