Added support for immediate block storage provisioning

 **Added support for immediate block storage provisioning**
  - Already exists in ec2 module
  - Syntax is the same as in ec2 module
 

    volumes:
         - display_name: vm1-vol1
           device_name: /dev/vdb
           volume_size: 10
           delete_on_termination: true
         - display_name: vm1-vol2
           device_name: /dev/vdc
           volume_size: 20
           delete_on_termination: false

  - `delete_on_termination` is not an openstack feature
    but will work during deletion

**Changed the authentication to Password() method**
  - Reflects most recent documentation
  - Necessary to switch between compute and volume
    actions if API URLs for those are different,
    which is true for a lot of installations