[FEATURE] Pending work items to launch extensions

[owaiskazi19]

Assumptions here:

1. Extensions will only run on a remote node/out of proc for initial launch.
2. If a plugin wants to run in-proc, then they can stay as a plugin until suppport for in-proc is built in extensions.

Pending work items for GA’ing AD extension: Meta Issue: https://github.com/opensearch-project/OpenSearch/issues/5224

• [ ] Security work for AD extension (especially Job Scheduler support)
• [ ] Multi-node support for AD extension https://github.com/opensearch-project/opensearch-sdk-java/issues/720
• [ ] Bringing the feature branch of AD extension in parity with main branch for AD plugin https://github.com/opensearch-project/anomaly-detection/tree/feature/extensions
• [ ] Explicit exception handling for AD extension APIs instead of a general exception.
• [ ] Throttle indexing based on indexing pressure https://github.com/opensearch-project/opensearch-sdk-java/issues/655
• [ ] Version decoupling feature support (for minor and patch versions) for AD extension
• [ ] E2E testing with Dashboard