Many small improvements

[drivera-armedia]

• Allow specification of a (relative) path via (configurable) annotations so the volume's path isn't necessarily so "cryptic", and instead can be more user-friendly. If the annotation is not provided, the default behavior is preserved.
• Added code to correctly compute the target path to delete when a volume is removed (the prior code didn't compute this properly)

You may only be interested in the modifications to the main go source, since the rest of the changes are fairly specific to our use of this code.