More Spells

## Detailed Description
There are a variety of spells currently in the game, but it would be great to have more.

## Context
Some spells could include:
    - Auras:
        - Health Aura: Heal the player by some amount each turn
        - Defence Aura: Up the players defence for some time
        - Berserk Aura: Up the damage dealt by the player
