Use Provenance resource instead of author extension

[katie-reynolds]

Extension: Author of the content

Multiple CH Core profiles use the "ch-ext-author" extension. Instead, consider using FHIR Provenance resources for this information, since this is the standardized way to communicate authorship of a resource.

[oliveregger]

This is a special extension to use within the vaccination and exchange formats, to differentiate the different authors here

https://fhir.ch/ig/ch-emed/authorship.html

It is needed for summary documents. Provenance might be used, but it would still need an extension to reverence the author.

[oliveregger]

Discussion: We need an extension to point to author in

RL: VACD: Provenance cannot directly solve it, an extension would still be used.
Daniel EMED: Will revisit when EU harmonization on Medication is done (but summary documents are not yet a topic there).

Most propably this extension can be removed R6.

ok to not change the extension: 11 - 0 - 0