feat(cli): implement SCRAM enhanced authentication for MQTT 5.0

[ysfscream]

What is the current behavior?

MQTTX CLI currently only supports basic username/password authentication for MQTT connections. It lacks support for MQTT 5.0 enhanced authentication mechanisms like SCRAM (Salted Challenge Response Authentication Mechanism), which provides stronger security through challenge-response protocols and salted password hashing.

What is the new behavior?

This PR implements SCRAM enhanced authentication support for MQTTX CLI, adding support for:

• SCRAM-SHA-1: SHA-1 based SCRAM authentication
• SCRAM-SHA-256: SHA-256 based SCRAM authentication
• SCRAM-SHA-512: SHA-512 based SCRAM authentication

New CLI Usage:

# Connect with SCRAM-SHA-256 authentication
mqttx conn -h broker.emqx.io -p 1883 -u username -P password --authentication-method SCRAM-SHA-256

# Publish with SCRAM authentication
mqttx pub -h broker.emqx.io -t topic -m "message" -u username -P password -am SCRAM-SHA-1

# Subscribe with SCRAM authentication
mqttx sub -h broker.emqx.io -t topic -u username -P password --authentication-method SCRAM-SHA-512

Key Features:

• Full MQTT 5.0 enhanced authentication flow implementation
• Integration with existing CLI commands (conn, pub, sub, benchConn, benchPub, benchSub)