[ENH] Add a utility for aggregating QA metrics on a cohort

[mattcieslak]

Idea

Make an entrypoint called something like qsiprep-aggregate that grabs QC data from the qsiprep outputs from a study and creates a CSV and/or json that can be loaded in a dmriprep-viewer-style app.

[richford]

Could this just be what happens by default when you change the usual BIDS-App participant parameter to group.

[mattcieslak]

I think in the long run we might save group for building an FOD template or something like that. I'm thinking we might be able to add some of the info into json sidecars that come out of the participant pipeline though, so you don't have to run an extra utility