Adding combat

[kodokoto]

Added a spell system, with validation, cooldown timers and a mana system to go with it.

Added 3 different spells:

• Teleport, which teleports the player at x distance in the direction of the mouse
• Shield, which gives the player immunity for x amount of time
• ProjectileSpell, which throws out a projectile

I also added a Player script which holds PlayerData and provides different methods for accessing properties and performing actions.

Furthermore, I also added a health and mana system, with automatic regeneration.