This PR adds tunings for the [newly announced](https://www.youtube.com/watch?v=ctkW3V0Mh-k) M3 family of chips. In particular, MetalRT will be enabled as the automatic default for intersection testing on M3 and beyond to take advantage of hardware raytracing. This will result in significant path-tracing speedups, as well as faster BVH builds.
Pull Request: https://projects.blender.org/blender/blender/pulls/114296
f2bb4c617f