[FEATURE] add a module-info.java to support JPMS properly

[SingingBush]

I'm currently trying to build a modular jar of my app that depends on:

<dependency>
    <groupId>org.opensearch.client</groupId>
    <artifactId>opensearch-rest-high-level-client</artifactId>
    <version>1.2.4</version>
    <scope>compile</scope>
</dependency>

but as the opensearch java clients don't have module-info.java files it's defaulting to try and do the modularity based on the classes in the file. This would potentially be okay if it wasn't for the fact that the org.opensearch.client package is available in two places.

module myapp reads package org.opensearch.client from both opensearch.rest.high.level.client and opensearch.rest.client

This is probably something that can be solved by properly supporting the module system.

[reta]

@SingingBush you may check opensearch-project/OpenSearch#1838, opensearch-rest-high-level-client depends on quite a few core modules which have to be modularized first

[SingingBush]

thanks for linking the existing ticket. The split packages problem will certainly need to be solved. I also noticed that the high level client pulls in a lot of transient dependencies that probably aren't needed.