cmd/plume: drop pre-publish from azure blob container list
cmd/plume: drop pre-publish from azure blob container list

it's only valid for the global region, so it can be a seperate step
using ore azure upload-blob.

marineam/mantle,glevand/coreos--mantle,quantum/coreos-mantle,dm0-/mantle,dm0-/mantle,quantum/coreos-mantle,glevand/coreos--mantle,marineam/mantle