[Docs] Add fileio tutorials (#420)

* docs(zh_cn/tutorials): add fileio tutorials

* Update docs/zh_cn/tutorials/fileio.md

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>