[Physics] Add dedicated CollisionListener sample project
In game engines such as Unity, functions like OnTriggerEnter, OnTriggerExit, OnTriggerStay, are used quite often. Simulant has a similar concept with its CollisionListener, but right now the only hint on how to use it is located in test_physics.h.
It would be great to have a small, dedicated sample which could show how to use the CollisionListener behaviour properly.