Add Hyper-V socket support to sshd

[aurel26]

PR Summary

Add Hyper-V socket support to sshd (AF_HYPERV).

PR Context

This PR allows to bind the SSH server on a Hyper-V socket, which can then be accessed via hvc ssh <VM NAME>.

This is useful for connecting via SSH (e.g. for VS Code between the host and a VM) without having an IP connection.

This is PR fixes half of PowerShell/Win32-OpenSSH#2200

To be enabled, the socket must be explicitly declared in sshd_config (ListenAddress 00000000-0000-0000-0000-000000000000).

[aurel26]

@microsoft-github-policy-service agree

[fw2568]

as this is still pending - we added a workaround here: https://github.com/eryph-org/guest-services

[hytecia9]

Thank you for your excellent work. I was looking for this exact patch.
However, I would like to report that building with v10.0.0.0 required upgrading _WIN32_WINNT in sshd-auth.
hytecia9@917001f

For Hyper-V enthusiasts, I've included a pre-built binary of v10.0.0.0 that supports Hyper-V sockets for x64, along with a simple usage guide.
https://github.com/hytecia9/openssh-portable-hyperv/releases/tag/v10.0.0.0-hyperv

If you don't trust the pre-built binaries, you can try building them yourself using the following instructions.
https://github.com/PowerShell/Win32-OpenSSH/wiki/Building-OpenSSH-for-Windows-(using-LibreSSL-crypto)

[gpotter2]

Hi @tgauth and very sorry for bothering. This PR brings cool improvements, I was wondering if you needed any help to make it go forward.

Something like adding unit testing, or maybe similar.

I understand it's a lot of work to keep the fork up-to-date with upstream, thanks a lot for your work !