Publish datasources module for downstream reuse in unified-ppl-2.19-dev

[Mebsina]

Description

Add datasources module

Local Publishing Test
Example after running the local publish command:

./gradlew publishUnifiedQueryPublicationToMavenLocal

tree -d ~/.m2/repository/org/opensearch
└── query
    ├── unified-query-api
    │   └── 2.19.0.0-SNAPSHOT
    ├── unified-query-common
    │   └── 2.19.0.0-SNAPSHOT
    ├── unified-query-core
    │   └── 2.19.0.0-SNAPSHOT
    ├── unified-query-datasources <- adding datasources 
    │   └── 2.19.0.0-SNAPSHOT
    ├── unified-query-opensearch
    │   └── 2.19.0.0-SNAPSHOT
    ├── unified-query-ppl
    │   └── 2.19.0.0-SNAPSHOT
    ├── unified-query-protocol
    │   └── 2.19.0.0-SNAPSHOT
    └── unified-query-sql
        └── 2.19.0.0-SNAPSHOT

Related Issues

3763

Check List

• New functionality includes testing.
• New functionality has been documented.
• New functionality has javadoc added.
• New functionality has a user manual doc added.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

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[opensearch-trigger-bot]

This PR is stalled because it has been open for 30 days with no activity.