Stundenplanprogramm: Create initial version of the school timetable program

[Emsel76]

This commit introduces a new command-line application for generating school timetables, specifically designed with the needs of a special needs school in mind.

The program includes the following key components:

• Data models for subjects, teachers, student groups, rooms, and timeslots.
• A backtracking scheduler that generates a conflict-free timetable based on a set of constraints.
• A command-line interface (CLI) for interacting with the program.
• A visual, grid-based display for the generated timetable, enhancing readability.
• A suite of unit tests to ensure the core scheduling logic is correct and robust.