WallManager binds to the BodyEntered signal on the Area2D class and
detects if the body that entered the area is the ball class, and if it
is, it will reset the ball to its starting position. right now, theres
no scoring system. this will be added later.
the enemy can now track the player with a cast that uses a shape generated in code. the enemy moves using some fancy math that gets the sign of the distance between the ball and the enemy paddles y position to get a normalised number for velocity and the velocity is lerped to smooth out any janky movement.
right now theres just a moving ball, inside a box, with a working paddle. i had to make the ball kinematic and tell the ball to bounce when it hits the other direction.
