This is a very simple thing to parse and format, but needs to be done
in 4 places, so two trivial utility functions have been made that can
be called from all the higher level parser/formatters:

  <domain><interface>
  <domain><interface><actual> (only in domain status)
  <network>
  <networkport>
Signed-off-by: NLaine Stump <laine@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>