[Proposal] Change quaternion representation from [w, x, y, z] into [x, y, z, w]

[yuecideng]

Proposal

Same as the title

Motivation

[x, y, z, w] convention is used as default by DexSim. Meanwhile the popular physics engine like newton or mujoco also use [x, y, z, w] conversion. So it maybe more straightforward to use this representation.

Checklist

• I have checked that there is no similar issue in the repo (required)