Merge pull request #42116 from vishh/gpu-experimental-support

Automatic merge from submit-queue

Extend experimental support to multiple Nvidia GPUs

Extended from #28216

```release-note
`--experimental-nvidia-gpus` flag is **replaced** by `Accelerators` alpha feature gate along with  support for multiple Nvidia GPUs. 
To use GPUs, pass `Accelerators=true` as part of `--feature-gates` flag.
Works only with Docker runtime.
```

1. Automated testing for this PR is not possible since creation of clusters with GPUs isn't supported yet in GCP.
1. To test this PR locally, use the node e2e.
```shell
TEST_ARGS='--feature-gates=DynamicKubeletConfig=true' FOCUS=GPU SKIP="" make test-e2e-node
```

TODO:

- [x] Run manual tests
- [x] Add node e2e
- [x] Add unit tests for GPU manager (< 100% coverage)
- [ ] Add unit tests in kubelet package

hack/verify-flags/known-flags.txt

@@ -690,3 +690,4 @@ windows-line-endings
 www-prefix
 zone-id
 zone-name
+