QEMU hide virtual machine from guest

To hide that we are a virtual machine, add these options to the virt-manager QEMU XML config of the virtual machine:

<domain type="kvm">
  <os firmware="efi">
    <smbios mode="host"/> <!-- This needs to be added -->
  </os>
  <qemu:commandline> <!-- This needs to be added -->
    <qemu:arg value='-cpu'/>
    <qemu:arg value='host,hv_time,kvm=off,hv_vendor_id=null,-hypervisor'/>
  </qemu:commandline>
</domain>