Enable kata-osbuilder-generate.service by default
    
    kata is an OCI container runtime that essentially wraps a qemu/kvm
    VM around around a traditional container image. Inside the VM runs
    a small appliance OS, containing the minimally needed kernel modules,
    systemd, the kata-agent, and not much else. This appliance is generated
    from host content, mostly using dracut.
    
    kata-osbuilder-generate.service is a oneshot startup service that
    generates the appliance for the boot kernel, and then exits. It's
    only installed when kata is installed.
    
    Signed-off-by: Cole Robinson <crobinso@redhat.com>