Implement import/export for SolidFire Driver

This adds the import/export (or manage) functioniality
to the SolidFire driver.

Partially Implements: blueprint add-export-import-volumes

Change-Id: I4e7d5fc7c66d8037f01efc47a4cf5e93d9dba662
Merge "Implement import/export for SolidFire Driver"