Update fields when a more complete author record is available

[willu47]

What currently happens:

1. An author exists in the database, but with an empty ORCID field
2. Metadata containing the author ORCID is available from a new publication
3. The code sees that the author is present
4. ...but does not update the record.

What should happen?

Step 3: The code sees that the author is present, but that the ORCID field is empty.
Step 4: The author's ORCID field in the database is written to, retaining the other data.

Potential issues

This relies upon the matching of author names (or other attributes) is accurate e.g. it would be possible to update an incorrectly matching author with the wrong ORCID.