Nordigen importer: include debtorName/creditorName

[redfast00]

In the Nordigen API, there's a debtorName/creditorName field (depending on if it's an incoming or outgoing transaction). This data is very useful for labeling transactiosn/setting the incoming and outgoing account when importing transactions; it would be nice if this were included in the import.

[tarioch]

added them to the metadata, let me know if you need anything else

[redfast00]

Thank you :D