Sale Order creation is now done in an interaction workflow triggered by the
instance state change.

Software/Slave instance workflow state should now be used to get the expected
status.

status will be not sent. log is not decided yet.

This will allow to directly associate Instance and Hosting Subscription

Creation just creates.

Access and use response object directly.

Thanks to this future compatibility can be easily achieved.

Avoid cluttering vifib_slapos_core.