[Tune] Add OSS Vizier to Ray Tune

[xingyousong]

Why are these changes needed?

We're adding OSS Vizier (https://github.com/google/vizier) to Ray Tune to increase reach and allow Ray users to use Google's hyperparameter optimizer, since it's been experimentally benchmarked to be one of the best.

Related issue number

None

Checks

• YES: I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• NO (I edited everything in Github GUI) I've run scripts/format.sh to lint the changes in this PR.
• N/A I've included any doc changes needed for https://docs.ray.io/en/master/.
  • YES I've added any new APIs to the API Reference. For example, if I added a
    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
• NO (I added tests but don't know how to install RayTune with a custom fork) 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
  • YES: Unit tests
  • YES: Release tests
  • NO: This PR is not tested :(

[github-actions]

This pull request has been automatically marked as stale because it has not had
any activity for 14 days. It will be closed in another 14 days if no further activity occurs.
Thank you for your contributions.

You can always ask for help on our discussion forum or Ray's public slack channel.

If you'd like to keep this open, just leave any comment, and the stale label will be removed.

[github-actions]

This pull request has been automatically closed because there has been no more activity in the 14 days
since being marked stale.

Please feel free to reopen or open a new pull request if you'd still like this to be addressed.

Again, you can always ask for help on our discussion forum or Ray's public slack channel.

Thanks again for your contribution!