Add Additional Fiels to participants.json

[ibevers]

Currently we only have description in the template. It would be beneficial to add more information.

BIDS participants.json example:

{
    "age": {
        "Description": "age of the participant",
        "Units": "year"
    },
    "sex": {
        "Description": "sex of the participant as reported by the participant",
        "Levels": {
            "M": "male",
            "F": "female"
        }
    },
    "handedness": {
        "Description": "handedness of the participant as reported by the participant",
        "Levels": {
            "left": "left",
            "right": "right"
        }
    },
    "group": {
        "Description": "experimental group the participant belonged to",
        "Levels": {
            "read": "participants who read an inspirational text before the experiment",
            "write": "participants who wrote an inspirational text before the experiment"
        }
    }
}

https://bids-specification.readthedocs.io/en/stable/modality-agnostic-files.html#participants-file

[Evan8456]

Similar to how participants.tsv is the super set of all the phenotype tsvs, particpants.json should be the combination of all phenotype json.