[FR] - Allow me to set an unique identifier to match against existing elements when importing category fields

[mikesnoeren]

We currently run a seperate feed to import our categories because we don't want the UID to be the title becuase the user should be able to change the title field without the feed recreating the old title and linking new items to it.

Currently I believe you can only choose UID for the main import element, and not when importing a category field and creating new elements if they don't exist yet..

Please, correct me if I am wrong!