rework FirstAuthor class?

[KonradHoeffner]

• We only have strings, do we need a class?
• It is a role, at least change FirstAuthor to Author or Person
• Use another predefined class with predicates first name, last name, ORCID ID and so on

[KonradHoeffner]

Options:

1. Use strings for authors, remove the class completely (my preference if nothing gets added)
2. use foaf:Person
3. use some existing Author class
4. keep the HITO FirstAuthor class but rename it to Author

[KonradHoeffner]

Use strings for authors, remove the class completely

We never get more than the single string, so use option 1.

• [x] remove the class
• [x] change the range of the property
• [x] rename the property from "hasFirstAuthor" to "firstAuthor"
• [x] remove the instances
• [x] replace occurrences of the instances with strings