Automatic merge from submit-queue

Remove implicit Prometheus metrics from client

**What this PR does / why we need it**: This PR starts to cut away at dependencies that the client has.

**Release note**:
<!--  Steps to write your release note:
1. Use the release-note-* labels to set the release note state (if you have access) 
2. Enter your extended release note in the below block; leaving it blank means using the PR title as the release note. If no release note is required, just write `NONE`. 
-->
```release-note
The implicit registration of Prometheus metrics for request count and latency have been removed, and a plug-able interface was added. If you were using our client libraries in your own binaries and want these metrics, add the following to your imports in the main package: "k8s.io/pkg/client/metrics/prometheus". 
```

cc: @kubernetes/sig-api-machinery @kubernetes/sig-instrumentation @fgrzadkowski  @wojtek-t