FGeometryCollectionConvexUtility::ComputeLeafHulls

Compute just the hulls of the leaf / rigid nodes that hold geometry directly, with no cluster hulls and no overlap removal by cutting This is an initial step of several algorithms: The CreateNonOverlappingConvexHullData function as well as convex-based proximity detection (TODO: and the auto-embed algorithm?) (TODO: Make auto-embed use this instead of the full hulls?)