Use Unit Ontology (http://bioportal.bioontology.org/ontologies/UO/?p=classes). Addjust Variable, Trait and Method IDs. Clean a few TraitIDs

add README in Vitis

As I start advertising the existence of the Vitis ontology in the vine & wine community, it is compulsory to have such a README with the basic set of information.

See merge request !1

Fix most of the duplicate generated in JSON. Cleanup script and switch to Postgres JSON generation. Fix GNP-4222