feat: add String localization support

Signed-off-by: The one with the braid <the-one@with-the-braid.cf>

README.md

@@ -21,6 +21,32 @@ Some parts of the PkPass specification are either not yet implemented, or not pl
 - `nfc`: Card payment information for Apple Pay. - Not planned, feel free to contribute.
 - `webService`: Information used to update passes using the web service. - Planned, feel free to contribute.
 
+## Localizations
+
+This package aims to implement PkPass localizations as well as possible. Any localizable value
+can be accessed using a `getLocalized...` method, e.g. `myPass.getLocalizedDescription()` taking a `Locale`
+as argument. In case the requested locale is not available, the following fallbacks are used:
+
+- `en` - English, any
+- `zh` - Chinese, generic language group
+- `hi` - Hindi
+- `es` - Spanish
+- `fr` - French
+- *In case neither available, take just any language you can find. We are likely dealing with a local product then.*
+
+The used fallback languages are the five mostly understood languages in the world, feel free to propose better or more
+precise fallback mechanisms.
+
+## Barcode encodings
+
+The PkPass standard is quite vague about the Barcode String encoding used. Technically, all IANA character set names
+are allowed. Since this might be some overhead to implement, the following encoders are supported by default:
+
+- `Latin1Codec` (default according to PkPass spec) - `iso-8859-1`, also fallback onto `iso-8859` and `iso8859`
+- `Utf8Codec` (most common one) - `utf-8`, also fallback onto `utf8`
+
+The supported encoders can be extended by adding a `String` `Encoder` pair to `PassBarcode.supportedCodecs`.
+
 ## Dependencies and compatibility
 
 Any package should keep its dependencies as minimal as possible. Sometimes, there are specifications making this