Implement initial battle system

[matthewjwhite]

What?

5 covers battle from a very high-level and undeveloped standpoint.

Battling should be further fleshed out to incorporate user statistics (see #7).

Blockers

This will likely need #7 before it can be started.

To Close

• [ ] Initial battle loop is created using user statistics to determine damage.
• [ ] Passing Pylint.