Aggregated parameter implementation

[todvora]

⚠️ Keeping for reference now, but I would not recommend merging it and rather use a different approach. This is too fragile, unpredictable and too much relying on conventions.

This PR implements following syntax for aggregated configuration properties:

@AggregatedParameter(prefix = "opensearch.", stripPrefix = true)
private Map<String, String> opensearchProperties;

Given following config properties file:

opensearch.node.roles=search,cluster_manager
opensearch.node.search.cache.size=10gb
opensearch.path.repo=/tmp

The map will be contain all three properties, with the prefix removed.

This is needed to support pass-through properties in the data node. All opensearch. prefixed properties will be forwarded to the opensearch process, without the need to explicitly support them in the data node.

Notes for Reviewers

• The commit history must be preserved - please use the rebase-merge or standard merge option instead of squash-merge
• Sync up with the author before merging

[moesterheld]

Thanks, this is what we need for easier pass-through of OpenSearch parameters to data node.
However, I think I found an error. Please also add readNames tests to the repository tests.

[todvora]

We decided for a different, simpler and more reliable implementation directly in the data node.