Adding sasl auth in kafka for agent

[Ark2307]

No description provided.

[Copilot]

Pull Request Overview

This PR adds SASL (Simple Authentication and Security Layer) authentication support to the Kafka client implementation, enabling secure authentication using username and password credentials.

• Introduces SASL plain authentication mechanism configuration for both Kafka writers and readers
• Adds environment variable support for authentication credentials and toggle
• Refactors transport/dialer configuration to support both TLS and SASL authentication simultaneously

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}