Clarify name/purpose of the 'author role' grouping

[mbrush]

The name 'author role' suggests that all roles captured for authors of a publication should come from this hierarchy. But this is not the case. Roles for publication authors can come from anywhere in the CRO - and indeed many of the original CREDIT roles meant for capturing contributions to pubs are not in the author role hierarchy (e.g. visualization role, resource provider role)

As the roles in the current 'author role' hierarchy are mainly related to preparation of the publication itself, consider renaming this to 'publication preparation role'? Or minimally, if the name is not changed, add some metadata that makes the purpose of this class clear, and that roles captured for authors of a publication can come from anywhere in the CRO.