ovirt_vm_info: add current_cd

[mnecas]

This PR adds usage of current_cd to the ovirt_vm_info.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1885542

Potential outputs:
when VM does not have any current_cd

            "current_cd": {
                "href": "/ovirt-engine/api/vms/293e855c-4477-41d3-959b-47e39ee120e4/cdroms/00000000-0000-0000-0000-000000000000",
                "id": "00000000-0000-0000-0000-000000000000",
                "vm": {
                    "href": "/ovirt-engine/api/vms/293e855c-4477-41d3-959b-47e39ee120e4",
                    "id": "293e855c-4477-41d3-959b-47e39ee120e4"
                }
            },

when current_cd is disabled

            "current_cd": {},

when VM does have current_cd

            "current_cd": {
                "file": {
                    "id": "CentOS-8.2.2004-x86_64-minimal.iso"
                },
                "href": "/ovirt-engine/api/vms/52b02ec8-95ba-4f2f-b6bb-4de2fd283fa2/cdroms/00000000-0000-0000-0000-000000000000",
                "id": "00000000-0000-0000-0000-000000000000",
                "vm": {
                    "href": "/ovirt-engine/api/vms/52b02ec8-95ba-4f2f-b6bb-4de2fd283fa2",
                    "id": "52b02ec8-95ba-4f2f-b6bb-4de2fd283fa2"
                }
            },

[mwperina]

+1