[Feature] Django register backend rework

[karastoyanov]

✨ Feature Description

Implement a user registration (signup) feature in the Django backend. Store the users in the PostgreSQL database(prod) in the related user model. Based the user model on the previous backend

🧩 Problem Statement

Currently, the backend lacks a secure and scalable user registration flow. This feature is essential to enable account creation while maintaining high standards of security and user experience.

💡 Proposed Solution

• Endpoint: Create a new API endpoint to handle user registration.
• User Creation: Accept user credentials (e.g., username, email, password) and create a new user in the database.
• Validation: Ensure proper input validation and error handling (e.g., duplicate email, weak password).
• Security: Hash passwords using Django’s built-in password hasher and enforce CSRF protection.

🔗 Related Issues / Links

• Related to [Feature] Django login backend rework #1

📋 Additional Context

• N.A.