* Cosmetics, renamed fields (eVtx, bVtx) -> (eVid, bVid)
* Multilayered delta architecture for Aristo DB
details:
Any VertexID or data retrieval needs to go down the rabbit hole and
fetch/get/manipulate the bottom layer -- even without explicit
backend.
* Direct reference to backend from top-level layer
why:
Some services as the vid management needs to be synchronised among all
layers. So access is optimised.