docs: describe prerequisite files with many links

[WillForan]

Descriptions, examples, and references for participants.tsv and scans.tsv.
Update note: ExperimentID is read from json for bold.

Link to NDA image03 and GUID Tools, nda-tools, web uploader, bids-validator, and BIDS spec for required but BIDS-optional files.

[yarikoptic]

minor formatting

[WillForan]

Thanks! Updated with all the changes.

Aside: I clicked commit changes on each suggestion in the webUI and then rebased locally. Any idea if there is more ergonomic way to accept all and collapse? Did I lose any important history or authorship doing that?

[yarikoptic]

Any idea if there is more ergonomic way to accept all and collapse?

you can stage multiple recommended changes and commit in a single commit while in "Files changed" tab

Did I lose any important history or authorship doing that?

I do not think so, looks good to me.