Haxe/hxnodejs externs for the dynamodb-data-types npm library

Tested using dynamodb-data-types version 2.1.6

Example:

import js.npm.dynamodb_data_types.AttributeValue;

AttributeValue.wrap({name: "Foo", age: 50});
// {"name":{"S":"Foo"},"age":{"N":"50"}} 

AttributeValue.unwrap({"name":{"S":"Foo"},"age":{"N":"50"}});
// {name: "Foo", age: 50}