[Spike] Create a detailed Game Design Document (GDD)

### What are we researching or investigating?

Brainstorm and create a game design document to outline core mechanics, art style, story, and gameplay features.

### Acceptance criteria

- A game design document (GDD) is planned out, documented, and published
- Feature stories are created to implement the design and features

### Suggestions

This document will be a "_living blueprint_" for the development process and is fine to have in a "draft" state as it may change overtime. However, a solid baseline should be planned out so that there's something solid to work off of. Things such as art style may change, but core mechanics should be thoroughly documented and thought out as they may be more challenging to change in the future.