Disable input field and button in piratebadge.html
Adding Future from dart:async lib.
Static empty lists for names and appellations, two static method stubs for parsing the names from JSON.
Implementing the two functions: performing GET asynchronously using Future, and sing the callback .then() after Future completes, then reading the names from the JSON file.
Stashing the span and the input elements in variables to avoid repeatedly querying the DOM.
Calling readyThePirates() from main(), if the Future successfully completes the then() callback function will be called that will enable the UI, else catchError() callback will be called leaving the UI disabled.