AuthService: Initialize Project Structure with Clean Architecture

[sentemon]

Description:
Set up the initial folder structure and base project configuration to follow the Clean Architecture principles. This will establish a solid foundation for the microservice's development.

Task:
Create the following project folders:

• Domain: For entities, interfaces, and domain logic.
• Application: For use cases, commands, queries, and validators.
• Persistence: For database and external service integrations.
• Infrastructure: Integrates external services (Keycloak API) and shared infrastructure.
• API: For endpoint, middleware, and API layer configuration.