Add kamon-opensearch

[rgprajeen]

As there is no support for instrumenting OpenSearch 1.x client even though the clients are vastly similar. I have duplicated the instrumentation for ElasticSearch and made the appropriate changes to support the OpenSearch client.

The changes can be summarized as below,

Change package names from com.elasticsearch.client to org.opensearch.client
Change all identifiers from elasticsearch to opensearch
Include necessary libraries

All test cases are green.

[rgprajeen]

Hi @hughsimpson , Could you please review this?

[hughsimpson]

This seems reasonable to me. Will try to get a passing CI build before merging (curse these flaky tests...)