Credits Screen

Credits should be recorded in a `credits.toml` file in the project root.

The credits file should contain:
- authors
  - full name of each author
  - username / handle
  - optional website
  - components of contribution
- external resources
  - author handle
  - license
  - URL

Game components for credits:
- Game Programming
- Graphics Programming
- 3D Assets
- Sound & Music
- Development Tools 