Add Windows SMB Volume Driver

Introduces a volume driver which makes use of SMB shares for hosting
volumes as disk images, having a similar workflow with the other NFS
like drivers.

This driver is based on the SMB Volume driver proposed for Linux,
overriding the platform specific methods.

It includes all the features required by the Juno release.

Driver cert results:
http://paste.openstack.org/show/100600/

The online snapshot related tests have been skipped as this
feature is not supported yet.

Change-Id: Idd5964690bca618c11fd116f80dd802d6cc2f31b
Implements: blueprint windows-smbfs-volume-driver
Merge "Add Windows SMB Volume Driver"