Split ship movement in several systems:
- ShipControl to handle events (mostly state transitions) of single ships
- ShipsMovement to handle the basic movement of the ship (this will update the position of the ship)
- ShipsMoving to handle ships that are in the 'moving' state
- ShipsOrbiting to handle ships that are in the 'orbiting' state

Using builders ensure that the correct components are added to a new created entity.

The 'GameState' resource stores the state of the whole game
(of a single client/player) so this is a better name for this.

Hint: The 'FleetControl' system is broken now, but will be refactored in the future anyway.

Plantes and asteroids are now recognized as obstacles for ships.