VSN-1925 : Corrected version of saving a new passenger functionality.

Passenger Module Implementation Summary

1. Passenger Service Interface

• Defined the PassengerService interface.
• Introduced the functionality for adding a passenger.

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2. Passenger Service Implementation

• Implemented the PassengerService interface.
• Provided the concrete logic for passenger operations.

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3. Data Validation

• Added data validation methods within the passenger service implementation.
• Ensured integrity of passenger input data before persistence.

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4. Saving a New Passenger

• Implemented the functionality for adding and saving a new individual passenger to the system.

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5. Passenger Controller

• Created the PassengerController class.
• Defined endpoints for passenger-related operations.

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6. Exposing Adding Functionality

• Exposed the endpoint to allow saving a new passenger via the controller layer.
• Integrated service logic with the controller for external access.

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7. Changelog Update

• Updated the changelog file to reflect recent changes in the passenger module.
• Documented implementation progress and structure.

Closes VSN-1925