oVirt is going to drop API v3 in version 4.2. We need to migrate to the new version
in order to be able to continue supporting oVirt as a compute provider. Expected path is:

1. take ownership of fog-ovirt to extract it from ovirt core https://github.com/fog/fog/issues/3942
2. migrate the fog code from rbovirt to https://github.com/oVirt/ovirt-engine-sdk-ruby to use the v4 API
3. update the foreman to use the updated backend

[1] - https://bugzilla.redhat.com/show_bug.cgi?id=1399750