Chart: add OpenSearch remote logging options

[topherinternational]

This change duplicates the existing elasticsearch configurations to support the new OpenSearch remote logging option added in #41799.

In addition to adding the opensearch block in values.yaml, it also adds a disambiguation check to prevent users from enabling both Elasticsearch and openSearch remote logging, as Airflow does not support using both at the same time.

Finally, a suite of tests is added to test the existing Elasticsearch configuration options as well as the new OpenSearch options. A few existing tests have been moved to put all of the ES/OS/remote logging behaviors under a single test module.