Enhancing concept models with internal notes (maintainer comments)

We need to enhance concept model with some kind of internal notes (maintainer comments). These internal notes are meant to be edited and read by glossary maintainers. They are not going to be included in RDFs, geolexica.org pages, etc.

The first question is how to name them. "Notes" is already taken. Perhaps "comments" is a good name for its conciseness, but I guess we may have other type of public comments in future. Other candidates are "internal notes" and "maintainer notes", but maybe someone has a better idea. I'll be calling them "comments" for the rest of this entry.

The second question is if these comments should be a collection of pure strings or a collection of some kind of structured data (body, created at, author, type). The latter is an especially good idea if we consider adding some automated comments in future like "X edited this concept on DATE". For your information, IEV spreadsheets contain comments which are going to be imported, and they are composed of date, body, and author. Perhaps we can turn them into a plain text, but I'm not sure of that.

The third question is if these comments should be associated with concepts, localized concepts, or either. Comments in IEV spreadsheets are clearly meant to be associated with localized concepts, and I suppose that we should attach them to localized concepts too, but there are not many of them, so if someone has some strong arguments for storing them at concept's root level, then perhaps we can merge them or something.