Add possibility of linking contributors at the edition level to author profiles

Contributors at the edition level (e.g. editors of the edition of a book, translators etc.) are coded as plain text, but it is not possible to link them to author profiles

### Describe the solution you'd like
The coding of contributors at the edition level should be done using author profiles

### Proposal & Constraints

### Additional context

No file, test, or entry point is named in the issue. Start by locating how edition-level contributors are represented and how author profiles are linked elsewhere; then trace the relevant data and UI paths. Done means edition-level editors, translators, and similar contributors can reference author profiles instead of only plain text.

Written by the indexing model from the issue text.