Add oVirt instance types / flavors support
note that [image provisioning] doesn't work well with the compute profiles, because both uses ovirt templates. Compute profiles can be reimplemented to utilize the new planned (ovirt 3.5?) feature instance type:
http://www.ovirt.org/Features/Instance_Types#Instance_Types_.28Flavors.29 once it will be implemented by ovirt.
Seems like we should reserve use of "templates" for image provisioning only, then have general provisioning and compute profiles use instance types instead.