Public preview: Node Resource Group (NRG) lockdown

Node Resource Group Lockdown removes the ability for customers to modify resources created as part of the AKS cluster.  Currently customers can directly modify and delete resources created by AKS, which can lead to an unstable environment.  To reduce these scenarios, NRG Lockdown applies a deny assignment to the node resource group, and any changes must happen through the AKS control plane.

To learn more, visit: https://aka.ms/aks/nrg_lockdown