This PR uses a slim win32 package JeffAshton/win_pdh since most win32 APIs needed are PDH API. Also this PR makes own implementation of GetPhysicallyInstalledSystemMemory until golang Windows syscall has it or lxn/win fixes opengl32 issue. Also this PR modifies the way to get Windows version.
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.
