cubicweb-medicalexp #3446640 ExternalResources -> FileSet, FileEntry [validation pending]

Change ExternalResources to FileSet across all Brainomics cubes, typically to be able to handle series of images, each image made of two files.

prioritynormal
typeenhancement
done in0.9.0
load1.000
load left0.000
closed by#bead41b1fa67 [schema, entities] ExternalResources -> FileSet + FileEntry
patch[schema, entities] ExternalResources -> FileSet + FileEntry [applied]