Support for Network_Storage notes

TODO:

1. Set notes for any Network_Storage volume.
Maybe a new command called `volume-set-note` ? I'd rather not add this to `volume-modify` since that is mostly about changing a volumes size. 
2. View notes in the volume-list (maybe limit this to 40 characters? )
3. View full notes in volume-detail


https://sldn.softlayer.com/reference/datatypes/SoftLayer_Network_Storage/#notes