Switch from Google Translate to OpenAI for Japanese docs translation

[lilin90]

The current quality of machine translation for Japanese docs is not so good. We need to consider other solutions. @shhdgit has tested OpenAI (as listed below), but still have some known issues (lost Markdown format, context alignment, overlarge size of a single .md file, etc.) to resolve.

https://github.com/pingcap/docs/blob/master/.github/workflows/translation.yaml
Previous testing https://github.com/shhdgit/docs-1/pull/8/files