Fix the wheel target, change to stable Python ABI

With the introduction of gRPC into VANet and the adaption of the IHTACMakeCommon, the wheel target broke. Especially gRPC caused issues with some build path being too long for MSBuild.

With these changes, the wheel target is being simpified using the package python-cmake-wheel. This package allow the wheeling of already build python bindings. As we already build the binding in out usual build tree this is very useful.

In addition, VAPython now uses the stable Python ABI which allows for the same binding to be used for Python versions >= 3.8. Note however, that this requires CMake version 3.26!