Added Constraints for Merge Tree Settings in ClickHouse

Why it matters

This feature addresses the need for tighter control over the configuration of MergeTree tables by preventing unauthorized or accidental changes to critical settings. It enhances security and stability by ensuring that certain important parameters remain enforced as intended by the database administrator.

How to use it

Administrators can define constraints for MergeTree settings by specifying which parameters are immutable or restricted from being overridden by users. This can be configured during table creation or by altering table settings, applying constraints to settings such as storage_policy to enforce policy compliance.