Allow configuring country and language in core config (#81734)

* Allow configuring country and language in core config

* Add script for updating list of countries

* Use black for formatting

* Fix quoting

* Move country codes to a separate file

* Address review comments

* Add generated/countries.py

* Get default language from owner account

* Remove unused variable

* Add script to generate list of supported languages

* Add tests

* Fix stale docsring

* Use format_python_namespace

* Correct async_user_store

* Improve typing

* Fix with_store decorator

* Initialize language in core store migration

* Fix startup

* Tweak

* Apply suggestions from code review

Co-authored-by: Franck Nijhof <git@frenck.dev>

* Update storage.py

Co-authored-by: Franck Nijhof <git@frenck.dev>

script/languages.py

@@ -0,0 +1,25 @@
+"""Helper script to update language list from the frontend source."""
+import json
+from pathlib import Path
+import sys
+
+import requests
+
+from .hassfest.serializer import format_python_namespace
+
+tag = sys.argv[1] if len(sys.argv) > 1 else "dev"
+
+req = requests.get(
+    f"https://raw.githubusercontent.com/home-assistant/frontend/{tag}/src/translations/translationMetadata.json"
+)
+data = json.loads(req.content)
+languages = set(data.keys())
+
+Path("homeassistant/generated/languages.py").write_text(
+    format_python_namespace(
+        {
+            "LANGUAGES": languages,
+        },
+        generator="script.languages [frontend_tag]",
+    )
+)