Add energy data

[cermakjn]

Implemented two EPs to get data from an energy (thermostats)

[philippelt]

Hello Jan,

many thanks for your contribution. I have no thermostat so I can't test your code but I assume you did it well.

I will merge your code as soon as you updated the associated documentation and preferably provide a sample program to illustrate it's use. Providing features without documenting them is rather a frustrating experience for peoples who could be interested by your work but do not have a deep knowledge of python.

Thanks in advance to include, at least, a documentation update to your merge request.

Phil