Boot from image destination - volume

Added class DriverImageBlockDevice that implements
creating volume from image on booting VM
from image if destination_type is volume.

Adding converting to legacy if source is image and
destination is a volume.

Change-Id: I8b8a7a2e40c083c18c4808b6b340360138086c1f
blueprint: improve-block-device-handling
Merge "Boot from image destination - volume"