Implement metrics for Windows Nodes

This implements stats for windows nodes in a new package, winstats.
WinStats exports methods to get cadvisor like datastructures, however
with windows specific metrics. WinStats only gets node level metrics and
information, container stats will go via the CRI. This enables the
use of the summary api to get metrics for windows nodes.

vendor/github.com/lxn/win/shobj_386.go

@@ -0,0 +1,24 @@
+// Copyright 2012 The win Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build windows
+
+package win
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func (obj *ITaskbarList3) SetProgressValue(hwnd HWND, current uint32, length uint32) HRESULT {
+	ret, _, _ := syscall.Syscall6(obj.LpVtbl.SetProgressValue, 6,
+		uintptr(unsafe.Pointer(obj)),
+		uintptr(hwnd),
+		uintptr(current),
+		0,
+		uintptr(length),
+		0)
+
+	return HRESULT(ret)
+}