Add button to restart single-player games

**Is your feature request related to a problem? Please describe.**
There is no button to restart a single-player game; you must exit the game and create it again with the same settings.

**Describe the solution you'd like**
Add a button to restart single-player games. Due to the individual ID system for each game, the game isn't actually restarted; instead, an identical game is created with the same parameters the user set when starting the game.

**Additional context**

**Assignment**

- [x] I'd like to be assigned to this issue and work on it myself