Write-Up draft data modell of nucleus
Write-up how PND and LNDs related to each other, representation of OND and non-ONDs etc. This has also to consider how so-called disaggregated devices are handeld, e.g., one can see a switch with SFPs as one single OND, and this one SDN agent (GNMI target), but there are more and more devices where a single OND can or is managed not by a single target, but the controller can directyl access the SFPs for configuration and monitoring.