VSN 445 : Introducing necessary Jpa Repositories to carry out mass sheet selection feature.

Setup of JPA Repositories for Mass Sheet Selection Feature

This merge request introduces the necessary JPA repositories to support the mass sheet selection feature within the preparation microservice. It marks a key step in structuring data access for entities related to passengers, roles, and transport schedules.

Key contributions include:

• Definition of repositories for Passenger, Role, and TransportSchedule entities
• Addition of foundational DTOs, including BaseDto and PassengerNameDTO
• Completion of all required repositories for mass selection logic

These additions effectively prepare the data access layer for upcoming functional developments.