Added AVG values for grid, PV and battery

There is user feedback, that the Wallbox does not stop charging when there is no power from the PV any longer. In order to support finding the root cause I have added the average values (for grid, akku & PV) the Wallbox records in order to see, if this might be the indication why the the charging-process does not stop (as expected from the user) - might be that the avg value would indicated that the box believes there is still enough PV power?!

Again - Please note, that this integration does not implemented a own PV surplus charging functionality - this integration can provide information for the Wallbox, so that the firmware of the device can/will support PV surplus charging. So I hope it's understandable for you, that it's beyond the control of the integration when the Wallbox will start or stop the (PV) charging process.

Of course there are other alternatives to implement PV surplus charging by adjusting/automate "everything" by your self - this of course can also be done via the number and switch entities of this integration. But so far I thrust the abilities of the go-eCharger firmware software engineers - so I don't see the need for that.