Introduce SSH protocol

Why it matters

This feature provides a secure and flexible way to connect to ClickHouse using the widely adopted SSH protocol. It solves the problem of limited connection options by allowing users to leverage standard SSH clients for database access, enhancing security and ease of use.

How to use it

To use this feature, configure clickhouse-server to enable SSH protocol support. Then connect to ClickHouse using any SSH client by specifying the appropriate server address and SSH credentials.