Complete WSL implementation, refactor a few areas

Also addresses a number of issues:
- StopHostNetworking isn't plumbed, win-sshproxy leaks on hyperv
- Wait api and print output doesn't work properly on Windows
- API forwarding doesn't work on WSL
- Terminal corruption with after start/stop on Windows
- Gvproxy is forcefully killed vs gracefully quit
- Switching rootful/rootless does not update /var/run/docker.sock on the guest
- File already closed error on init
- HyperV backend is publishing Unix sockets when it should be named pipes
- User-mode networking doesn't always work
- Stop state outside of lock boundaries
- WSL blocks parallel machined (should be supported)

[NO NEW TESTS NEEDED]

Signed-off-by: Jason T. Greene <jason.greene@redhat.com>

pkg/machine/ssh_unix.go

@@ -0,0 +1,16 @@
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd
+
+package machine
+
+import (
+	"os"
+	"os/exec"
+)
+
+func setupIOPassthrough(cmd *exec.Cmd, interactive bool) error {
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	return nil
+}