Removing ms-nyu images which are in sct-testing-large

[plbenveniste]

I realised while doing the QC of the MS datasets that t most subjects in ms-nyu were in sct-testing-large.

In this issue, we detail the work done to remove these images from sct-testing-large.

[plbenveniste]

The following script was written to solve this code/remove_nyu_subj.py. It does the following:

• for each sub-nyuShepherd file, it checks if the file exists in ms-nyu. If not, it is copied to the right location (with the corresponding json file).
• same for the derivative files. This was essential sice vertebral discs and spinal cord seg were not all in ms-myu

Then I removed the files from the csv file.

Ready for review and merge!