SPAR ontologies

Discussion started with including by-line order in the schema (done in #26), keep it now for discussion about contribution role and spar ontologies.

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How to code order of authors in the byline ? This should also integrate the `*these authors contributed equally ` information, maybe using some more informative elements than a footnote ?

Most schemas I saw do not encode it, but the order of the element signals it.

I could not see anything about co-frisco-firstt authorship elements in jats4r, did I miss it (@hubgit ?)

So far, I only saw crossref integrating an element with indication of `sequence = oneof( first, additional, last)`(https://www.crossref.org/education/content-registration/descriptive-metadata/contributors/#00009, last is not indicated here, but I did see it in some downloaded data).

Start by reading issue #18 and the completed related work in #26, then compare the cited Crossref contributor sequence guidance with JATS4R authorship elements. Clarify the intended representation for byline order, equal contribution, and contribution roles, and document the agreed schema behavior; no implementation file or test is identified.

Written by the indexing model from the issue text.