Add batch queries support to improve performance and handle row limitations

[t4nz]

This pull request introduces batch query logic to the WP REST Cache plugin. The goal is to enhance query performance and ensure compatibility with environments that impose per-query row limits (e.g., PlanetScale, which limits rows returned, updated, or deleted to 100k).

Changes included
• Implemented batch queries to split large database operations into smaller chunks.
• Ensures queries respect per-query row limitations imposed by some database environments.
• Improved performance for large datasets by processing queries in batches.
• Added safeguards to maintain data consistency during batched operations.

Benefits
• Prevents query failures in environments with strict row limits.
• Improves stability and compatibility with cloud-hosted databases (e.g., PlanetScale).
• Enhances performance for large-scale cache operations.

Notes
• Backward compatible — existing installations will continue to function without configuration changes.
• Tested with large datasets to validate performance improvements and stability.