VMware: OVA and StrOpt images as VM templates

Optimize instance creation on VMware by keeping images as VM templates per datastore. The workflow would be to import image as VM (per datastore), mark that VM as template, and then create the actual (instance) VM by cloning the template VM for the image. The current approach is to import image as VM, cache the VM disk, unregister VM, and then create actual (instance) VM anew using the cached disk. The functionality could relatively easy be implemented to be configurable so that one can choose between the new approach and the old one.