Thermostat/Climate: Add Valve Opening Information

[mrueg]

My thermostat (homematic) includes a valve sensor (0-100%).

It would be really helpful to visualize that valve sensor in the thermostat card as well.

As an example in this screenshot:

The state Heating could include an additional entity value (in this case the valve opening), so this would become for example: Heating (23%)

This would also be useful for other climate devices (e.g. levels or fan speed for AC)