Fixes for building python wheels on manylinux2014 (#6947)

Fixes for building python wheels on manylinux2014 (#6947)

This PR makes several fixes to the wheel building infrastructure for manylinux2014.

don't statically link to Python (see: this section of PEP-513)
use standard 'build' directory. I noticed that the wheel infrastructure uses directory 'build' to prepare the wheel anyway, so it doesn't make a lot of sense for us to use a separate working directory. I tried changing the name of the build directory in setuptools by setting member variables in initialize_options but that didn't seem to work and I decided it wasn't worth the effort. The wheel should be built in a clean environment anyway, i.e., docker.
find the correct include directory and python library paths for building on manylinux2014 using skbuild. manylinux2014 has several versions of python installed in /opt/python. The CMake infrastructure can't find the necessary information (plus the libraries are deleted from the docker image to save space -- the library is just set to a generic libpython<version>.a). Instead, this PR would manually set them via CMake options.
to allow setting the python information, I extended the configure.sh script to allow directly setting CMake options. There are definitely other options here if you'd rather not change configure.sh. My reasoning was that it could be useful in other situations and I just marked it as an advanced feature. Another approach would be to use skbuild directly in the CMake infrastructure. I didn't like that solution because it would make the CMakeLists.txt more complicated and it wouldn't follow the standard CMake/Cython/Python approach which means we won't benefit from future improvements to that CMake infrastructure. Plus, this issue should only come up on systems with non-standard installations of Python, such as manylinux. This approach (setting CMake options) is basically what scikit-build does automatically if we had used that infrastructure directly.