Document Packaging Godot Games

## Problem

There aren't many games being built for elementary OS at the moment and that's a shame. It would be nice to give indie game developers the same path to monetizing and distributing as indie app developers

## Proposal

We've talked before about documenting the process of Flatpaking games, in particular using the Godot game engine since it's open source

## Prior Art

An issue report for documenting Godot Flatpaks exists here with some information on how to build an example: https://github.com/godotengine/godot-docs/issues/2993