Add typing to homeassistant/*.py and homeassistant/util/ (#15569)

* Add typing to homeassistant/*.py and homeassistant/util/

* Fix wrong merge

* Restore iterable in OrderedSet

* Fix tests

homeassistant/__main__.py

@@ -20,7 +20,7 @@ from homeassistant.const import (
 )
 
 
-def attempt_use_uvloop():
+def attempt_use_uvloop() -> None:
     """Attempt to use uvloop."""
     import asyncio
 
@@ -280,8 +280,8 @@ def setup_and_run_hass(config_dir: str,
         # Imported here to avoid importing asyncio before monkey patch
         from homeassistant.util.async_ import run_callback_threadsafe
 
-        def open_browser(event):
-            """Open the webinterface in a browser."""
+        def open_browser(_: Any) -> None:
+            """Open the web interface in a browser."""
             if hass.config.api is not None:  # type: ignore
                 import webbrowser
                 webbrowser.open(hass.config.api.base_url)  # type: ignore