Add Github Actions workflow for building libacfutils on github runners.

[todirbg]

This adds workflow for building libacfutils on Ubuntu 20.04 and MacOS 12 runners. The binary release libacfutils_redist folder is saved as an artifact and can be downloaded after workflow execution. The built dependencies are saved in cache and are reused to speed up later builds. All dependencies are rebuild if there is a change in any of the source archives( tar archive files). The workflow is set to be executed manually. This is useful to people that do not have access to mac or linux hardware and want to build recent libacfutils for all platforms. First run, when dependencies are built, takes about 12 minutes on linux runner and 20 on macos runner.