Add author to UNFCCC metadata

[joel-wright]

Description

Adds author to UNFCCC metadata from the input CSV

Type of change

Please select the option(s) below that are most relevant:

• Bug fix
• New feature
• Breaking change

How Has This Been Tested?

Existing tests extended.

Reviewer Checklist

• The PR represents a single feature (small driveby fixes are also ok)
• The PR includes tests that are sufficient for the level of risk
• The code is sufficiently commented, particularly in hard-to-understand areas
• Any required documentation updates have been made
• Any TODOs added are captured in future tickets
• No FIXMEs remain

[diversemix]

Looks good ... we could add another test to navigator-backend/tests/core/ingestion/test_unfccc_ingest_row.py to check that the meta data of author has been added during ingest too for completeness?