Add Plugin Support for Xenia Emulator

📋 Summary

Add official plugin support for Xenia, the leading Xbox 360 emulator, enabling smoother integration, setup, and game launching within LaunchBox.

🎯 Feature Overview

• Automate download and initial setup of Xenia

• Recognize and associate supported Xbox 360 file types (e.g. .iso, .xex)

• Offer built-in configuration options from the LaunchBox emulator settings panel

• Automatically assign Xenia to compatible Xbox 360 games upon import