Rittal CMC CAN Bus Device Discovery added

I modified the code to discover not only the Rittal CMC III Processing Unit Sensors but also the connected CAN Bus Devices.

You can connect many Access and Sensor Devices via CAN Bus to the Processing Unit, but they were not display by Observium.

With the attached Patch you will be able to see the sensor for each Device.

Hope nothing is broken with this.. but if you want to verify - i attached a snmpwalk of such device.