Async gather wait (#4247)

* Fix config validation for input_*, script

* Allow scheduling coroutines

* Validate entity ids when entity ids set by platform

* Async: gather -> wait

* Script/Group: use async_add_job instead of create_task

homeassistant/helpers/script.py

@@ -85,7 +85,7 @@ class Script():
                 def script_delay(now):
                     """Called after delay is done."""
                     self._async_unsub_delay_listener = None
-                    self.hass.loop.create_task(self.async_run(variables))
+                    self.hass.async_add_job(self.async_run(variables))
 
                 delay = action[CONF_DELAY]