Document SaveLoad

[dogo]

Summary

Add Save/Load Dialog Functionality with Documentation

This PR introduces the SaveLoad module, enabling save, load, and delete operations with the following features:

• Dialog Initialization: Functions to initialize save, load, and delete dialogs, including multi-list, single, and automatic options.
• Data Structure: The oslSaveLoad struct, which holds all relevant data like game title, save name, and associated assets (icons, images).
• Lifecycle Management: Functions to manage dialog display, status retrieval, and finalization.
• Doxygen Documentation: Full documentation for easy integration and understanding.

This update streamlines game save/load management with a well-documented, flexible interface.