Could you check/add trv.valve.position?

[Bascht74]

Hi, I am using the viessmann thernostats, that are allready working with the integration.
If you want to see, that your setup is working fine, you sometimes need the date from the valve.

Viessmann is using trv.valve.position for that.
Is it possible to check, if that information is available in the api, too?

Thx for this repository anyway! It is very helpful!