cmd/tailscaled: move more of the Windows server setup code into tailscaled

Updates #1232

paths/paths.go

@@ -8,6 +8,7 @@ package paths
 
 import (
 	"os"
+	"path/filepath"
 	"runtime"
 )
 
@@ -42,5 +43,8 @@ func DefaultTailscaledStateFile() string {
 	if f := stateFileFunc; f != nil {
 		return f()
 	}
+	if runtime.GOOS == "windows" {
+		return filepath.Join(os.Getenv("LocalAppData"), "Tailscale", "server-state.conf")
+	}
 	return ""
 }