(Reuters) – China’s 20th Communist Party Congress began on Sunday, with Xi Jinping poised to clinch his third five-year stint in charge – a mandate that would secure him as the country’s most powerful ruler since founding leader Mao Zedong. * Xi opened the week-long, twice-a-decade session with a speech touting China’s fight against COVID-19, the party’s safeguarding of national security, maintaining social stability, protecting people’s lives and taking control of the situation in Hong Kong, which was rocked by anti-government protests in 2019. He also called for accelerating the building of …