MQTT convert to async (#6064)

* Migrate mqtt to async

* address paulus comment / convert it complet async

* adress paulus comment / remove future

* Automation triggers should be async

* Fix MQTT async calls

* Show that event helpers are callbacks

* Fix tests

* Lint

tests/common.py

@@ -86,7 +86,13 @@ def async_test_home_assistant(loop):
     loop._thread_ident = threading.get_ident()
 
     hass = ha.HomeAssistant(loop)
-    hass.async_track_tasks()
+
+    def async_add_job(target, *args):
+        if isinstance(target, MagicMock):
+            return
+        hass._async_add_job_tracking(target, *args)
+
+    hass.async_add_job = async_add_job
 
     hass.config.location_name = 'test home'
     hass.config.config_dir = get_test_config_dir()