Support folder structure for non multi-file

[rbosker]

Is your feature request related to a problem? Please describe.
In Multi File we currently support grouping of sets, which can be used to create a folder structure.

Describe the solution you'd like
Make it possible to add folders/groups for sets. This should work the same as the feature in Multi File:
Simply renam token sets to have a folder path, eg folder/set-1 , folder/set-2

Currently nothing happens when using this terminoligy, without having multi file.

Additional context

Initial ticket for fixing this in multi file: #315