HCL: GRAFENTHAL PR-3000-HS supported by snmp-ups

Tested with 2.6.5-3 (0.68) on Windows (IETF MIB 1.4).

Some NUT variables are zero - further testing may be needed.

Reference: http://news.gmane.org/find-root.php?message_id=75FC7A5479BA4A4E8ADF76BC3AD3E568581EC753%40MS03.MACLE.DE