[Core][Autoscaler] Refactor v2 Log Formatting

[ryanaoleary]

Why are these changes needed?

Currently the V2 Autoscaler formats logs by converting the V2 data structure ClusterStatus to the V1 structures AutoscalerSummary and LoadMetricsSummary and then passing them to the legacy format_info_string. It'd be useful for the V2 autoscaler to directly format ClusterStatus to the correct output log format. This PR refactors utils.py to directly format ClusterStatus. Additionally, this PR changes the node reports to output instance_id rather than ip_address, since the latter is not necessarily unique for failed nodes.

Related issue number

Closes #37856

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 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.
• 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 :(

[ryanaoleary]

cc: @rickyyx, I think I'm going to add some different unit test cases but this should be good to review