Add/update Senturion Environmental Manager (sensatronics-em1)

A Sensatronic Senturion SFE020 can be added to LibreNMS and is recognized as a “sensatronics-em1” type device. The device can be polled using SNMPv1 and returns data. (see supplied links). The defined OID’s in the YAML file (/opt/librenms/includes/definitions/discovery/sensatronics-em1.yaml)
do not correspond with the OID’s supplied by the device. The device supplies the data but is not graphed.

(Imported from, Original request by: @SandMouse)