Allow building with meson and meson-python
The scipy and numpy communities chose meson over CMake and migrated to meson. With https://github.com/FFY00/meson-python they have a modern and actively maintained "backend" for pip and pypa/build. Unfortunately scikit-build (the CMake-equivalent) is in much worse shape and does not seem to be actively developed anymore.
This MR adds support for meson while keeping support for CMake.