Convert switch to AsnycIO (#4382)

* Convert switch to AsnycIO

* Move update entity to service

* use time better for faster handling

* Change to suggestion from paulus

* Use new shedule_update_ha_state

* fix lint

* minimize executor calls

homeassistant/components/switch/demo.py

@@ -66,9 +66,9 @@ class DemoSwitch(SwitchDevice):
     def turn_on(self, **kwargs):
         """Turn the switch on."""
         self._state = True
-        self.update_ha_state()
+        self.shedule_update_ha_state()
 
     def turn_off(self, **kwargs):
         """Turn the device off."""
         self._state = False
-        self.update_ha_state()
+        self.shedule_update_ha_state()