Added ClickHouse Keeper CLI Client

Why it matters

This feature introduces a dedicated command-line interface for interacting with ClickHouse Keeper, simplifying management and operations related to distributed consensus coordination within ClickHouse. It enhances usability by providing a native tool tailored for Keeper tasks, eliminating the need for external clients or complex scripts.

How to use it

Users can access the ClickHouse Keeper CLI by running the clickhouse keeper-client command from the terminal. This client supports various Keeper administrative commands, enabling direct interaction with the Keeper service.