Add a github workflow to build XDP programs for ebpf-for-windows

[dthaler]

Currently XDP programs are only built for Linux, but ebpf-for-wIndows supports XDP programs as well.
Since we want L3AF to be cross-platform, this issue tracks adding the ability to build for Windows.
The repository might have some Linux-only programs, some cross-platform programs, and theoretically even some Windows-only programs.
So we need a way to know for each program, which platforms are supported, and then build those programs on each platform.