Align the resouces' metadata types with the corresponding of GeoNode 5

[Gpetrak]

GeoNode 5 metadata includes some differences in metadata types compared with the ones expected from QGISGeoNode plugin. For example regarding the UUID, QGISGeoNode plugin expects the UUID to be an object while GeoNode defines UUID as a string. We should review and align the metadata types that QGISGeoNode plugin expects from GeoNode 5.