I'm going to grab the Rapier physics library so that I don't have to do
my own collision detection mechanism. The last time I did this, I
simplified everything into circles. This time I'd like to have convex
hulls, particularly for the player ship.
Also the last time, I ended up rolling my own quadtree impl. I'm not
particularly interested in doing that again, and I'd like to learn more
of the broader Bevy ecosystem.
The ship, such as it is, exists and moves when the player presses "W".
Position is updated according to velocity, and the mesh transform is
updated to match the position.
