(Beta) Azure KeyVault Flex Volume

[mathieu-benoit]

https://vincentlauzon.com/2019/02/21/flex-volume-in-aks/

It looks like FlexVolume won't be GA and its replacement will be CSI:

• https://github.com/deislabs/secrets-store-csi-driver
• https://kubernetes.io/blog/2019/01/15/container-storage-interface-ga/