Add to the config file for generalization of BIDS structure

[adam2392]

1. subject: passed in through subjects.tsv
2. session: hard-coded as one variable
3. task/acquisition/recording: None

We should also make sure the entire workflow is BIDS-compliant with "derivatives". The issue is that derivatives such as robustfov and acpcdetect should be stored separately, and there are a lot of sidecar files that need to be written, so we need functions to do that.

Documentation on file format

Need to also document that we "Requires .nii files to be BIDS-compliant."

[adam2392]

To allow generalization of setup of BIDS structure, it is I believe safe to assume user either starts with:

i) dicoms
ii) nifti file

To then obtain data in BIDS, I'm going to allow there to be a DAG workflow for:

• using heudiconv based on our heuristic.py file to get dicoms -> acceptable format
• use mne_bids.write_anat / manual conversion to put into folder structure format

Assuming at the very minimum, we have the BIDS structure NIFTIs, then everything else downstream is possible without assuming too much.