[tools] model_explorer_circle package generation and publish

[seanshpark]

Let's enable model_explorer_circle package generation and publish to pypi.org

[seanshpark]

• sub task of #14307

[seanshpark]

I'll follow basics from https://github.com/pypa/sampleproject/

[seanshpark]

README.md will be used as description of the package in pypi.org. Current file contains How to generate Circle schema python script which would be better to exist in some separate how to file. Let's split this.

[seanshpark]

Need to add MANIFEST.in file for package generation

• reference https://setuptools.pypa.io/en/latest/userguide/miscellaneous.html#controlling-files-in-the-distribution