* Move tools docs to `tools` folder.
* Fix link error in model_serving.md
* Fix typo in CONTRIBUTING.md
* Add Chinese translation of CONTRIBUTING.md
* Add translation of `onnx2tensorrt.md`, `pytorch2onnx.md`,
`model_serving.md` and `pytorch2torchscript.md`.
* Improve tools docs.
* Add docs about installing mmcls via mim.