[FEATURE] - Authentication and Authorization Mechanisms

[aeldin]

Add a mechanism for authenticating and authorizing clients, including username/password authentication and access control based on client roles.

1. Username/Password Authentication:
   Implement a mechanism to require clients to provide a valid username and password during the connection handshake. This ensures that only authenticated clients can connect to the server. The credentials can be stored securely on the server side, and the client must provide the correct combination to establish a connection.

2. Access Control Based on Client Roles:
   Introduce the concept of roles for clients, allowing you to define specific permissions or access levels for different clients. For example, you might have clients with roles like "admin," "publisher," or "subscriber." Based on the role, you can enforce restrictions on actions such as publishing or subscribing to specific topics.