Include LICENSE file in Python distribution

[chrisjbremner]

I have tooling in place to pull the license text from packages using pip-licenses. I noticed, however, that ortools does not include the license file in its Python distribution, and as a result, it is difficult to pull in the license file from the project, especially since there is no link back to the Github repo in the Python package (https://developers.google.com/optimization/ is listed as the package URL).

I am proposing including the LICENSE file in the Python distribution by copying the License in as part of the python.cmake file. By doing so, it will get picked up by setuptools since it defaults to including files that match the following patterns: 'LICEN[CS]E*', 'COPYING*', 'NOTICE*', 'AUTHORS*' as described in code here or in the docs here (under license_files).

In addition, I removed the setup_data.py since it seemed like an outdated version of setup.py.in which appears to be what has been used recently. Please correct me if I shouldn't have removed this.

I will note that I have yet to be able to test this since I don't have the full toolchain set up.

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[Mizux]

Also in pyproject.toml (since setup.py seems deprecated AFAIK)
https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#license

[chrisjbremner]

Just checking -- is that a request to convert to using pyproject.toml for packaging instead of setup.py in this PR, or are you simply pointing out that doing this in pyproject.toml is a possibility in case that's used in this project in the future?

[Mizux]

Just checking -- is that a request to convert to using pyproject.toml for packaging instead of setup.py in this PR, or are you simply pointing out that doing this in pyproject.toml is a possibility in case that's used in this project in the future?

AFAIK setup.py is slowly being deprecated so it is good to know that this LICENSE stuff is also compliant with the toml approach so the day we [have to] migrate we already have a clean shape.