[BUG] Document task consumer integration

[JeffHuss]

Issue: opensearch-project/OpenSearch#1009
PR: opensearch-project/OpenSearch#2293

[JeffHuss]

Reached out to Sruti on Slack. I see movement for this feature - only a failed gradle check is blocking the merge so it seems likely to make 2.2. Neither the original issue nor the associated PR seem to include a detailed description of how this new functionality would be implemented or leveraged by a user. Will need to do some information sourcing and testing this week to confirm.

[JeffHuss]

Still waiting on info from devs. Got a link to a Quip doc covering observability which I'll take a look at but I will need to be able to test this functionality.

[JeffHuss]

I have a sync with the dev scheduled for this afternoon for a quick demo of the feature and a short Q&A. I was presented with a feature doc that includes the usage of the feature. This is an API function only - will need to review the API template and document organization.