We have a perf test that has been used to compare Ammo vs. PhysX
https://c-frame.github.io/physx/examples/pinboard/ammo-vs-physx.html

This depends on some minor updates to aframe-physics-system to report timing data, which aren't in this fork yet.

We should:

• Being these changes into this fork (possibly controlled by a proprerty in the main physics schema)
• Bring this example into this repo's examples, including cannon and cannon-worker versions
• Quantify the perf difference between Ammo and Cannon in the README section that gives advice on which driver to use.