Change object file processing

[duck-bongos]

Currently I read from the .obj file and write the pixels (regex w/ Python: re.findall("vs\ .*", read)) and voxels (regex w/ Python: re.findall("v\ .*", read)) to two separate .txt files.

Given the ease at reading and extracting the appropriate values using regular expressions, proposal to enhance the current pipeline's function mediapipe_mesh/src/utils.py: process_obj_file to use regular expressions to return numpy arrays of the pixels and voxels.

[duck-bongos]

I think most of the code is written, just need to put it all together properly