Implement and test different mechanics

[gy-toxyc]

The purpose of this issue is to implement and test different mechanics into the game engine, without those being previously designed. From these ideas, we will define the videogame.

Tasks

• [x] Implement basic movement system.
• [x] Implement attack system.
• [ ] Improve this attack system with distance attacks.
• [x] Implement stats system.
• [x] Implement the correct behaviour of all the stats system.

In order for this issue to be closed, all tasks should be completed.

[gy-toxyc]

We found a really scalable way to do the "ability system" for each player, and implemented it correctly. From now on, we will test different ability types, in order for the system to be as powerful as possible.