SOLR-18093: Add top-level 'queries' support to JsonQueryRequest in SolrJ

[ercsonusharma]

https://issues.apache.org/jira/browse/SOLR-18093

Description

Currently, JsonQueryRequest in SolrJ supports specifying a single query via setQuery() and other top-level parameters like limit, sort, fields etc.

However, it does not support top-level "queries" blocks, which is a good addition to fully leverage the combined query component and the Additional Queries feature in Solr’s JSON Query DSL. This limitation prevents constructing multiple queries or additional scoring/re-ranking queries in a single JSON request from the client side.

Solution

Added method to pass the required params in JsonQueryRequest. Also, enhanced the documentation.

Tests

Added Unit tests and Integration tests.

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide
• I have added a changelog entry for my change