Add validate API

[Naarcha-AWS]

Issues Resolved

Closes https://github.com/opensearch-project/documentation-website/issues/2104

Version

List the OpenSearch version to which this PR applies, e.g. 2.14, 2.12--2.14, or all.

Checklist

• [ ] By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and subject to the Developers Certificate of Origin. For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[Naarcha-AWS]

@msfroh: Would you mind performing a tech review on this one?

[Naarcha-AWS]

@gbbafna: Can you take a look at this one?

[Naarcha-AWS]

@natebower: Resolved.

[Naarcha-AWS]

@natebower: This should be ready for your approval.