Split code into modules for better readability and maintainability

[CesarVielmas]

The current code is contained in a single large file, making it hard to manage and scale. This enhancement proposes separating game objects (player, enemies, platforms, etc.) into independent classes and files.

Suggested tasks:

Create separate classes for each object type

Use inheritance if applicable (e.g., base GameObject class)

Reorganize project folders and files

Add documentation for each module