Azure AKS nodes not identified by powerfulseal

[tceduard]

Issue

When running powerfulseal in AKS, the nodes that make up the cluster are not accounted in the inventory of nodes that powerfulseal creates. This affects all node scenarios targeting AKS nodes, but works ok with stand-alone VMs.

Proposed solution

To be able to include the AKS nodes in the powerfulseal inventory, the AKS Virtual Machine Scale Sets are queried and its instances are translated into powerfulseal node types for them to be added to the inventory.

#316