Set Up Basic Action, Domain, and Responder Structure

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Establish the foundational structure for the phalcon/rest-api-v6 project by creating the core components for request handling and business logic separation.

Requirements:

• Implement an Action layer for processing incoming requests and orchestrating application flow.
• Establish a Domain layer to encapsulate business logic and core rules.
• Create a Responder layer for formatting and returning responses to clients.

Tasks:

• Define interfaces and base classes for Actions, Domains, and Responders.
• Set up initial directory structure for each component.
• Document the responsibilities and usage patterns for each layer.

Benefits:

• Promotes clean architecture and separation of concerns
• Improves code maintainability and testability
• Provides a scalable foundation for future feature development

[niden]

Implemented in #12