Create sensor class for SEL2001 device in ts_ess_common.

Upon inspecting the ESS common code and attempting to implement the sensor, I discovered that the temperature sensor module implements the same type of sensor. I then discussed with Wouter how to add the configuration to the ESS such that it could see the sensor on laserrpi.tu.lsst.org which is still pending a decision regarding where the implementation belongs.

This ticket covers the work inspecting and attempting to implement the sensor before realizing that the sensor is done and the conversation with Wouter.