Support SCRAM-SHA-256 authentication

Why it matters

This feature enables ClickHouse to use the secure SCRAM-SHA-256 authentication mechanism when clients connect via the PostgreSQL protocol. It improves security by providing a more robust authentication method compared to older methods, helping users protect their database connections.

How to use it

When configuring ClickHouse to accept connections via the PostgreSQL protocol, the authentication method can be set to SCRAM-SHA-256 in the user's authentication settings. Ensure the client supports SCRAM-SHA-256 and configure connection parameters accordingly for successful authentication.