[EPIC] Basic player combat

[eric-blue]

This is a pretty broad one, but what we want to do is create a combat system via a new MODULE for the player

Right now, there is a keypress event on the PlayerController that triggers an "ATTACK!" so we want to move this into it's own module and add to it

• [x] both players and NPCs need to track health somehow #17
• [x] display health in a new UI HTML overlay => https://github.com/eric-blue/feywild/pull/26
• [x] the actual action of triggering a player attack, or receiving an attack from an npc => https://github.com/eric-blue/feywild/pull/27
• [x] should have a timed function that cycles through a new character sprite for the attack animation => https://github.com/eric-blue/feywild/pull/27
• [ ] new character sprite sheet for that ^
• [x] some sort of event triggered via a CustomEvent that the enemy accepts and decrements some sort of health count => https://github.com/eric-blue/feywild/pull/27