Update Change 74593 (New ord Network Models)

Explore possibility to handle ietf-network yang model update (8345) through multiple Yang revisions in Change 74593. The target is to be able to merge 74593 on Neon with no errors when running functionnal tests.
Update ord network models to R4.0, which includes reference to the latest update of ietf network models. The addition of a Network container on the top of the hierachy implies to modify all the code refering to items that depends on the topology tree. Push code based on new network model after rebase and inclusion of available ord models. Implies to check before that there is no interaction between Network model 4.0 and device model 2.1