Auto-restart games after power outage

When a power outage occurs, the games don't automatically restart when power is restored.

Add a script/service that runs on boot to automatically start the games so the Xavier is ready to go without manual intervention.

**Suggested approach:** systemd service or init script that launches the main game launcher on boot.

**Platform:** NVIDIA Jetson Xavier NX (Ubuntu 20.04, JetPack 5.0.2)