FR: Add option to add more data to the Generator in the WHEEL file

[ofek]

ref: pypi/warehouse#12436 (comment)

So users can tell which version of setuptools was responsible for builds

[fungi]

In particular, PEP 517 build backends which leverage the wheel library's writer (in order to not reinvent the....) could benefit from being able to plumb generator metadata through somehow. This includes SetupTools as a build backend, as well as other backends which extend SetupTools (e.g. calling into the setuptools.build_meta.build_wheel() method), but theoretically could also apply to non-SetupTools-based backends as well.