Add Delete QueryGroup API Logic

[ruai0511]

Description

This change introduces the Delete QueryGroup API which we will use to enforce node level resiliency as part of this RFC: #12342. The draft PR opened for the API specs is: opensearch-project/opensearch-api-specification#356

The Delete QueryGroup API schema is:

curl -XDELETE "localhost:9200/_wlm/query_group/{name}"  // delete the QueryGroup with name={name}

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Failing checks are inspected and point to the corresponding known issue(s) (See: Troubleshooting Failing Builds)
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)
• Public documentation issue/PR created

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[github-actions]

✅ Gradle check result for aa293e9: SUCCESS

[github-actions]

✅ Gradle check result for 3d65bf5: SUCCESS

[github-actions]

❌ Gradle check result for 28e4755: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[kaushalmahi12]

If the failures are unrelated should we merge the PR?

[jed326]

If the failures are unrelated should we merge the PR?

Retried the checks. Maintainers don't have ability to merge failed checks.

[github-actions]

✅ Gradle check result for ff9a93e: SUCCESS