implement option for using cibuildwheel
this MP implements an option to build C-code for manylinux, windows and macos using cibuildwheel
and the gitlab runners of the codebase gitlab (https://hifis.net/doc/software/gitlab/ci/)
I will add a demo package to test this implementation, but it has already been successfully implemented in psyplot/psy-ugrid!6 (merged)