[Feature Request] Provide an option to pick an app to autolaunch when game mode boots up

[Daeymon]

Since this plugin already has the functionality to launch apps, I wondered if it could go the extra step, and have a setting where we could pick an application to be automatically launched when game mode boots. Basically when the plugin is initialised by decky loader.

One user case for this would be to automatically launch an alternative frontend for the Steam Deck, such as RetroDECK.

[Fisch03]

Souns like a great addition! I'll look into it :)