Clarification on authentication vs authorization

As previously mentioned, I found the use of the terms "authorization" and "authentication" in the primer especially, but also in the spec, to be confusing.

@justinwb tried to explain to me the Editors meeting that the use of authorization comes from OAuth, where the idea is that the user authorizes an agent to act on their behalf, and that's fine.

However, Solid has maintained a clean separation between authentication as in "figure out who this user is", and authorization as in "figure out if they are allowed to access this resource". It is important to ensure that this architectural property isn't compromised. For what I've read, it doesn't seem that it has been, but the wording may lead people into thinking that the distinction isn't important, or just confuse them.

Therefore, I believe this should be clearly explained, at least the primer, but perhaps in an introductory note in the spec.

As publishing it on solidproject.org/TR will attract a new readership, I believe this is something that should be done before we publish it there. As we discussed this briefly in the Editors meeting, it seemed to be some agreement around that.