implement std.Progress IPC for Windows

[andrewrk]

Extracted from #20059.

Currently, on Windows, std.Progress is implemented for the root process that owns the terminal, however it is not able to collect progress information from the child processes that it spawns.

This issue can be closed when child processes using std.Progress on Windows communicate their progress to parent processes.

A simple way to test this would be adapting this example to also work on Windows:

https://gist.github.com/andrewrk/b22b4f663cef6b4672d7097de95ea343

For POSIX systems this is implemented by a dedicated pipe file descriptor that is passed from parent to child, much like stdio streams. It should be possible to do something equivalent on Windows.