Allow importing from subfolders of local directory

[FlorianMF]

It would be cool if the UDT could ... allow the user to import samples inside of subfolders of the chosen directory on the local storage. For the moment, only files lying directly inside the chosen folder can be loaded. A greater file structure complexity is not allowed.

For many datasets, it is indeed completely OK to simply have all files inside a folder. But, for instance for medical image datasets, its interesting to keep the folder structure. Thanks

[seveibar]

Thanks for the suggestion @FlorianMF, I totally agree!

[FlorianMF]

FYI, using a nested structure isn't a problem I you directly modify fields 'imageUrl' the udt.json file. But that's quite more complicated than importing the images in the UDT