* Create pyproject.toml
* Implement a custom build backend (see below) in packager directory. Build logic from setup.py has been refactored and migrated into the new backend.
* Tested: pip wheel . (build wheel), python -m build --sdist . (source distribution)
* [CI] Automatically build GPU-enabled R package for Windows
* Update Jenkinsfile-win64
* Build R package for the release branch only
* Update install doc
