### What problem does this PR solve?
Refactor /api/v1/chats to be more RESTful.
### Type of change
- [x] Refactoring
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Co-authored-by: Jin Hai <haijin.chn@gmail.com>
### What problem does this PR solve?
Searches /search API to RESTFul
### Type of change
- [x] Documentation Update
- [x] Refactoring
Co-authored-by: Jin Hai <haijin.chn@gmail.com>
Co-authored-by: Yingfeng <yingfeng.zhang@gmail.com>