use gvisor-tap-vsock

[sakai135]

Use gvisor-tap-vsock instead of VPNKit.

I added some modifications to make gvisor-tap-vsock communicate between its vm Linux and gvproxy Windows processes over stdio instead of Hyper-V sockets. This removes the need for registry changes and admin privileges and also works in a multi-user environment by letting the native WSL 2 integration handle the underlying connection.

Improvements:

• DNS resolver that hides IPv6 without NXDOMAIN, which should help with busybox/Alpine issues
• remove use of socat/npiperelay, less processes, mitigates npiperelay is flagged as malicious software #78
• bypasses Windows processes show as windows when running with WSL Preview  #61

TODO:

• make IP settings configurable
• update docs