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>

tests/test_core.py

@@ -948,6 +948,8 @@ async def test_config_defaults():
     assert config.safe_mode is False
     assert config.legacy_templates is False
     assert config.currency == "EUR"
+    assert config.country is None
+    assert config.language == "en"
 
 
 async def test_config_path_with_file():
@@ -989,6 +991,8 @@ async def test_config_as_dict():
         "external_url": None,
         "internal_url": None,
         "currency": "EUR",
+        "country": None,
+        "language": "en",
     }
 
     assert expected == config.as_dict()