Allow rollershutter to close to state 0

https://goswagger.io/use/models/schemas.html#nullability

move.go

@@ -17,7 +17,7 @@ func Move(state *State, shutters []string, position int64) {
 		m := &models.ModulePercentage{
 			Bridge:         state.ModuleStatus[state.ModuleForName[x]].Bridge,
 			ID:             state.ModuleForName[x],
-			TargetPosition: position,
+			TargetPosition: swag.Int64(position),
 		}
 		updates = append(updates, m)
 	}

swagger.yaml

@@ -327,6 +327,7 @@ definitions:
       target_position:
         description: percentage open
         type: integer
+        x-nullable: true
 securityDefinitions:
   OAuth2:
     type: oauth2