Refactor thermal grid energy demand

[danielfeismann]

resolves #928

merge #895 and #927 first

[danielfeismann]

House got overheated again Point 4

Once the house has reached the upper temperature level, the heat from the HP is used to charge the thermal storage. At the next arrival of weather data, the thermal house will be triggered again to determine an updated state. In the current version of handleInfeed(), the thermal input into the storage is set to zero to use the heat for the house first. This heats the house again until the upper limit is reached, and so on...

With the changes proposed so far, the hp will now run to heat the house first, then charge the storage, but will continue to run as the house cools down while the storage is being charged, and will therefore have a possible additional heat demand which will then be covered by the hp. Therefore, the demand calculation for the next state needs to be adjusted to only have an additional demand when the inner temperature is below the target temperature.
see operatesInNextState()
demand.hasRequiredDemand || (state.isRunning && demand.hasAdditionalDemand)

Point 5 Hp runs longer than expected

Should be fixed by calculating the actual state within ThermalGrid.energyDemand()

Point 10 qDot result still positive when storage is already full

Should be fixed by calculating the actual state within ThermalGrid.energyDemand()

[sebastian-peter]

These are my comments for now, will look deeper later

[sebastian-peter]

Looks good, let's get this bad boy in.