Add HMAC(algorithm, message, key) sql

Why it matters

This feature adds support for generating HMACs directly within ClickHouse queries, enabling secure message authentication and integrity verification. It simplifies workflows by allowing cryptographic operations inside SQL without external processing.

How to use it

Use the HMAC function in SQL queries with three parameters: the hashing algorithm name (e.g., 'SHA256'), the message string, and the secret key. For example:

SELECT HMAC('SHA256', 'message', 'secret_key') AS hmac_value;