Automatic merge from submit-queue (batch tested with PRs 52168, 48939, 51889, 52051, 50396). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..
Add Windows Server Containers Stats and Metrics to Kubelet
**What this PR does / why we need it**:
This PR implements stats for Windows Server Containers. This adds the ability to monitor Windows Server containers via the existing stats/summary endpoint inside the kubelet. Windows metrics can now be ingested into heapster and monitored using existing tools (like Grafana).
Previously, the /stats/summary api would consistently crash the kubelet on Windows server containers. This PR implements a new package "winstats" which reads windows server metrics from a combination of windows specific perf counters as well as docker stats. The "winstats" package exports functions that return CAdvisor data structures, which the existing summary api can read.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#49398
This PR addresses my plan to implement windows server container stats https://github.com/kubernetes/kubernetes/issues/49398 .
**Release note**:
```release-note
Add monitoring of Windows Server containers metrics in the kubelet via the stats/summary endpoint.
```
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