Implemented ZooKeeper Four Letter Words Commands in ClickHouse Keeper

Why it matters

This enhancement addresses the need for comprehensive administrative control and diagnostics within clickhouse-keeper by implementing all standard ZooKeeper Four Letter Words commands. It enables users to perform operations such as status checks, connection stats, and configuration management directly, improving observability and maintainability.

How to use it

Users can execute the full range of ZooKeeper Four Letter Words commands against clickhouse-keeper just as they would with ZooKeeper. For example, using tools like netcat or telnet, send the standard commands (e.g., ruok, stat, conf) to the clickhouse-keeper listening port to retrieve cluster and server information.