sysutils/sispmctl: New port to manage EnerGenie and Gembird USB controlled power strips

SIS-PM Control is an application for managing USB controlled powerstrips produced by
GEMBIRD LTD. Newer devices are sold under the Energenie brand.
The following devices are supported:
 * Gembird MSIS-PM
 * Gembird Silver Shield SIS-PM (aka Revolt Intelliplug)
 * Gembird Silver Shield SIS-PMS
 * Energenie EG-PM
 * Energenie EG-PMS
 * Energenie EG-PM2
 * Energenie EG-PMS2