Map deprecated categories to the 'new' categories 

Map deprecated categories to the 'new' categories. Currently it remaps
only the d23-d26 categories since these are the only categories that have clearly defined new
categories (https://github.com/Spotnet/Spotnet/wiki/Category-Codes).
The result is a cleaner genre column.

Spots already in the database are not touched. I'm not sure whether or not these should be updated as well. It would make it easier when creating filters.