cubicweb-datacat #5099515 [dcat] better use the Distribution class [validation pending]

The Distribution class could be used to directly represent a Resource of a Dataset. This would be more compliant with DCAT-AP specification.

prioritynormal
typebug
done in0.3.0
load left0.000
closed by#2ccb0d1f4117 Associate resource files to distribution instead of dataset directly
patchAssociate resource files to distribution instead of dataset directly [applied][schema,hooks] Relate a ResourceFeed to a Distribution [applied][schema] Add a title attribute to ResourceFeed, rename uri to url attribute [applied]