ElyesDer

**Description** This PR fixes an issue with incompatible [ISO 639-3](https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPInternational/LanguageandLocaleIDs/LanguageandLocaleIDs.html) codes between iOS's [Locale](https://developer.apple.com/documentation/foundation/locale) and Amazon Polly's [ISO 639-3](https://docs.aws.amazon.com/polly/latest/dg/SupportedLanguage.html). It was also reported [here](https://github.com/mapbox/mapbox-navigation-ios/issues/1977#issuecomment-809467252). **Implementation** - [x] Store all unsupported...