QC images: populate one group at a time instead of one modality at a time

Add:

for group in qcimg:
  for q in group.split('|')

in place of: https://github.com/AMP-SCZ/eeg-qc-dash/blob/b618b5368073092275ba67ef8b919aeb6def6da9/app.py#L369

Again, we can have both groups and individual modalities in:

[tb571@eris2n5 data_from_nda]$ cat eeg_qc_images.csv
img,default
_QCcounts,1
_QCimpedance,1
_QClineNoise,1
_QCbridge,1
...

Then we need np.unique(qcimg) before the above line to move forward. The user would be responsible to include modalities of choices at least once--by group or individually!

AMP-SCZ / eeg-qc-dash

QC images: populate one group at a time instead of one modality at a time #23