Uniformize .json files for .tsv's first column to be "<entity>_id"

[yarikoptic]

We have participant_id in subjects.tsv, session_id in sessions.tsv, BUT we just ran into name being first column in _channels.tsv https://bids-specification.readthedocs.io/en/stable/modality-specific-files/intracranial-electroencephalography.html#channels-description-_channelstsv ... worth reviewing all .tsv files on that aspect.

edit 1: I even wonder if this should be taken as an opportunity to make all of them into just a value (as a generalization over index and label) or actual {entity} (e.g. subject or session) instead of {entity}_id which then includes {entity}- prefix (e.g. sub-01), which was always unclear to me on why to bother duplicating that obvious prefix.

But also here I am somewhat mixing up two different kinds of tabular files -- subjects sessions and samples correspond to entities. But we do not have entity "channel" for _channels.... so may be two issues in one