Add detection of Red Hat's hypervisor

Add detection of Red Hat's hypervisor

Red Hat sets the following fields in SMBIOS information, allowing us
to detect that it's the branded Red Hat hypervisor.

  Manufacturer: Red Hat
  Product Name: KVM
  Version: RHEL 7.6.0 PC (i440FX + PIIX, 1996)

Note that "RHEL 7.6.0" there is the machine type, which is not the
same as the hypervisor version (although the two have a relationship).

Thanks: Timothy Smith at IBM, Karen Noel