Add 1g0rrr/demo2_frame_holder (v3.0, structural v2.1->v3.0 only (not an SO-100/101 dataset); joint values left unchanged)

Add 1g0rrr/demo2_frame_holder2 (v3.0, structural v2.1->v3.0 only (not an SO-100/101 dataset); joint values left unchanged)

initial commit