[weather] Add Support for LanguageCode to WeatherFactorys constructor.

### Description
I would like to just pass the languagecode to the WeatherFactory instead of Language enum. Is there a special reason why this enum was introduced? Cause in _buildUrl the enum is converted to languagecode anyway. So for me its unnecessary complexity to convert the `Localizations.localeOf(context).languageCode` to packages Language enum and then the packages just convert it back to languagecode.

Alternative, please add a constructor `.fromLanguageCode` to the Language enum.

Best Regards
Micha