Fix SetDemandControl

Since there is no way to get the current value of demandcontrol, HA listens to the same topic where we send the command.
Thus when users set DemandControl to 20%, we send "81.2" via mqtt. HA
reads that value and tries to cast it to an int.

fix #252

custom_components/aquarea/definitions.py

@@ -353,14 +353,14 @@ def bit_to_bool(value: str) -> Optional[bool]:
 
 
 def read_demandcontrol(value: str) -> Optional[int]:
-    i = int(value)
+    i = float(value)
     if i >= 43 and i <= 234:
         return int((i - 43) / (234 - 43) * 100)
     return None
 
 
 def write_demandcontrol(value: int) -> str:
-    return str(value / 100 * (234 - 43) + 43)
+    return str(int(value / 100 * (234 - 43) + 43))
 
 
 def read_smart_grid_mode(value: str) -> str: