(Reuters) -Ximalaya, backed by China's Tencent Holdings, filed for an initial public offering (IPO) in the United States on Friday, cashing in on growing demand as more people tune in to podcasts while staying at home during the pandemic. China's Qiniu Ltd, a cloud-based platform-as-a-service provider backed by Alibaba Group Holding Ltd, also filed paperwork for a U.S. IPO