Add Plugin Support for Cemu Emulator

📋 Summary

Introduce official plugin support for Cemu, the leading Wii U emulator, to simplify setup and enhance game launching through LaunchBox.

🎯 Feature Overview

• Automatically download and configure Cemu within LaunchBox.

• Detect and associate Wii U titles (including .wud, .wux, and Loadiine formats).

• Provide built-in options to adjust graphics packs, input profiles, and game-specific settings.

• Optionally support title key management and shader cache handling.