Automatic merge from submit-queue
decouple workqueue metrics from prometheus
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**What this PR does / why we need it**:
We want to include the workqueue in client-go, but do not want to having to import Prometheus. This PR decouples the workqueue from prometheus.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
Partially address https://github.com/kubernetes/kubernetes/issues/33497
User requested for `workqueue` in client-go: https://github.com/kubernetes/client-go/issues/4#issuecomment-249444848
**Special notes for your reviewer**:
**Release note**:
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```release-note
The implicit registration of Prometheus metrics for workqueue has been removed, and a plug-able interface was added. If you were using workqueue in your own binaries and want these metrics, add the following to your imports in the main package: "k8s.io/pkg/util/workqueue/prometheus".
```
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