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
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