Built-in component for top-down movement

[AlmasB]

Consider pacman, bomberman and battletanks games. They have very similar code wrt movement that can be provided in a component.

Collisions vs the world cells / tiles should be considered.

[AlmasB]

CellMoveComponent and AStarMoveComponent work nicely together for use cases where entities move using cells. For other "free" type movement, we need TopDownMoveComponent, which also considers collisions.

[AlmasB]

//    private List<Entity> blocks;
//
//    private void move(double dx, double dy) {
//        if (!getEntity().isActive())
//            return;
//
//        if (blocks == null) {
//            blocks = FXGL.getApp().getGameWorld().getEntitiesByType(PacmanType.BLOCK);
//        }
//
//        double mag = Math.sqrt(dx * dx + dy * dy);
//        long length = Math.round(mag);
//
//        double unitX = dx / mag;
//        double unitY = dy / mag;
//
//        for (int i = 0; i < length; i++) {
//            position.translate(unitX, unitY);
//
//            boolean collision = false;
//
//            for (int j = 0; j < blocks.size(); j++) {
//                if (blocks.get(j).getBoundingBoxComponent().isCollidingWith(bbox)) {
//                    collision = true;
//                    break;
//                }
//            }
//
//            if (collision) {
//                position.translate(-unitX, -unitY);
//                break;
//            }
//        }
//    }