cmake for python packages

cmake_python.txt

Hi @atilag ,

Thanks for the kind words 😄

> Is there a way to create a wheel package that is agnostic to this `site/dist-pacakges` problem?

Instead of using

```
install(TARGETS my_extension LIBRARY DESTINATION ${PYTHON_RELATIVE_SITE_PACKAGES_DIR})
```
I suggest you use something like:

```
install(TARGETS my_extension LIBRARY DESTINATION name_of_package)
```
where `name_of_package` is the python package name.

This is similar to the `hello` package name used in this [example](https://scikit-build.readthedocs.io/en/latest/usage.html#example-of-setup-py-cmakelists-txt-and-pyproject-toml), the corresponding `setup.py` can also be found in the [hello-cpp](https://github.com/scikit-build/scikit-build-sample-projects/tree/master/projects/hello-cpp) sample project.