Collider and trigger glTF Object Model JSON pointers

[aaronfranke]

https://github.com/eoineoineoin/glTF_Physics/tree/master/extensions/2.0/Khronos/KHR_physics_rigid_bodies

The physics bodies extension contains several JSON pointers at the bottom of the document. However, none of the collider and trigger properties are listed here. Was this intentional? I think they should be, even if defined as read-only properties if the desire is to not have them be mutable, but it could potentially be useful to define these as mutable.