base link and base footprint should be updated w.r.t the REPs

[padhupradheep]

https://www.ros.org/reps/rep-0120.html

ROX and the real robot packages for the MP platforms follows the conventions.

[AdarshKaran]

The current setup with base_link as the child of base_footprint follows the REP convention. However, the srdf files for both mpo_500 and mpo_700 in neo_mpo_moveit2 had to be updated with the relevanth <disable_collision> tags which fixed the issue.