Implement Service-Agnostic Context for Notification Service

[iammuho]

The goal of this issue is to build a service-agnostic context for the Notification Service from scratch. By employing a factory pattern, we aim to provide the Notification Service the flexibility to adapt different notification service providers (like Firebase, OneSignal, etc.) without impacting the internal workings of the system.

Tasks:

• Define an interface that outlines the essential methods for notification operations such as Send, Receive, Delete, UpdateStatus, etc.
• Implement a factory pattern to instantiate the appropriate notification service provider based on configuration or runtime requirements.
• Develop an initial implementation using a placeholder or dummy notification service that adheres to the defined interface.
• Integrate this factory and interface into the existing Notification Service codebase.
• Write unit tests to confirm that the Notification Service works as expected with the dummy implementation.

Acceptance Criteria:

• Notification Service should be able to operate with different notification service providers without changes to the internal services.
• Unit tests confirm that the new implementation meets the expected behavior.