Add energy sensor for LG Washer

[ooghes]

The latest LG ThinQ app updated the "Energy monitoring" feature by adding a view on the hourly, daily, weekly and monthly energy consumption of the washer (in Wh or kWh). It also shows the cumulative energy consumption. It's a big improvement compared to older app versions which only showed bars without actual values or legend.

It would be great if the existing Home Assistant integration would be extended with a sensor that shows the cumulative energy consumption on an hourly basis. In doing so, a sensor with state_class "total_increasing" becomes available, allowing Home Assistant to track the hourly/daily/monthly/yearly energy consumption associated with the washer and integrate it in the Energy view.

An alternative would be to add a smart plug in the socket that provides power to the washer, but that would not leverage the built-in functionality offered by the washer.

I'm using an LG washer GC3V708S2 TurboWash 39.

[ooghes]

Linked to issue #748