[draft][autoscaler] Node preference plugin

[wuisawesome]

Why are these changes needed?

Related issue number

Checks

• [ ] I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• [ ] I've run scripts/format.sh to lint the changes in this PR.
• [ ] I've included any doc changes needed for https://docs.ray.io/en/master/.
• [ ] I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • [ ] Unit tests
  • [ ] Release tests
  • [ ] This PR is not tested :(

[DmitriGekhtman]

I think you forgot to git add the new file ray.autoscaler._private.loader.

[DmitriGekhtman]

I know it's a draft, but could you add a PR description?

[stale[bot]]

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[stale[bot]]

Hi again! The issue will be closed because there has been no more activity in the 14 days since the last message.

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