libvirt: Select image type in runtime according to mapping parameter for OpenStack Compute (nova)

Let nova compute be more flexible in selecting resulting image type rather than strictly during initialization via images_type configuration parameter. In this case, if a hypervisor is able to understand different types of images allow it to work natively with provided image without converting.

Virtuozzo containers config drive support for OpenStack Compute (nova)

Virtuozzo containers currently lacks a support of config drive. We can do it by two ways: 1. via ploop block device which is mounted to /var/lib/cloud/seed/config_drive on container's filesystem. Cloud-init considers this path as one of sources of data without any additional changes. 2. via host directory bind moun...