Fix compilation review doc

[Matisse-M]

This pull request significantly improves the documentation and onboarding experience for the Ryan R-Type project. The main changes include a comprehensive overhaul of the README.md with clearer instructions, troubleshooting, and updated usage details, as well as the addition of new Docusaurus documentation covering features, installation, and entity/map creation. There is also a minor code fix for metrics rendering in the game client.

Documentation Improvements

• Major rewrite and expansion of README.md:
  • Added a detailed project overview, feature list, system requirements, quick start guide, troubleshooting section, and clarified installation steps for different platforms. Also improved instructions for running and building documentation with Docusaurus and Doxygen. [1] [2] [3] [4]
• Added new Docusaurus documentation pages:
  • features.md: Comprehensive list of game and technical features.
  • installation.md: Step-by-step installation and build instructions for all platforms, including troubleshooting and Docker support.
  • creating-maps-mobs-projectiles.md: Guide for defining entities, projectiles, and maps using JSON and Lua scripts.

Codebase Fixes

• Fixed a type conversion bug in InGameState.cpp to prevent potential rendering issues with in-game metrics by ensuring consistent float-to-size_t conversion.

These changes make the project easier to install, understand, and contribute to, while also addressing minor technical issues in the client code.