Add possibility to set offset temperatur value

[chrissooo]

Device type and model (or SN)

P0000000Q104XXXXXXXXXX

The description of new feature

My Air Confitioners inDoor temperatur sensor shows the temperatur to high. If is it 21°, its show ~3,5° to much. is it possible to add a config possibility to set a delay for it?

I have do it manuel and change the set_temperature and current_temperature and add +3,5° by reading and set +3,5° on set and its work. Of course, on the devise its shows a wrong temperatur, bit i use only HA to set and read data and its ok for me.