[Feature] Implementation of Halpe_68 (no face)

[davidpagnon]

What is the feature?

It would be quite useful for the biomechanics community if you provided a pose estimator for the Halpe_68 keypoints (full-body with feet and hands but no face): https://github.com/MVIG-SJTU/AlphaPose/blob/master/alphapose/datasets/halpe_68_noface.py

Any other context?

I would then implement it in RTMlib, and integrate in the Pose2Sim markerless mocap solution.