Add variant and card UID in the API #1127

Variants allow slicers to read and identify filament (I believe). I noticed this when adding snapspeed filament, without the variant as SnapSpeed the slicer identified it as generic PLA. Adding the variant got the slicer to correctly identify it as SnapSpeed.

Idea is to have when adding a Filament via RFID scan of a spool to read "subtype" and add that to Spoolman as variant text. Right now the REST API doesn't allow for variant to be pushed.

Same is for card UID, currently it is missing in the REST API. If added to the API other apps could add spools to Spoolman database with the read UID tag, skipping the step having to add the UID manually for filament use tracking.