By Chen Aizhu (Reuters) – Russia has agreed a 30-year contract to supply gas to China via a new pipeline and will settle the new gas sales in euros, bolstering an energy alliance with Beijing amid Moscow’s strained ties with the West over Ukraine and other issues. Gazprom, which has a monopoly on Russian gas exports by pipeline, agreed to supply Chinese state energy major CNPC with 10 billion cubic metres of gas a year, the Russian firm and a Beijing-based industry official said. First flows through the pipeline, which will connect Russia’s Far East region with northeast China, were due to sta…