Add i18next framework to enable further contributions (#96)

* prototype

* Update with comments and type safety

src/plugins/i18n.ts

@@ -0,0 +1,42 @@
+import i18next from 'i18next';
+import { menu as enMenu } from '../locales/en/menu';
+import { menu as itMenu } from '../locales/it/menu';
+
+const DEFAULT_LANGUAGE_OVERRIDE = '';
+
+/**
+ * i18next is a localization library for maintaining and using translation resources.
+ * 
+ * Q: How do I add a new language?
+ * A: To add a new language, create a new folder in the locales directory with the language code.
+ *    Each language folder should contain a file for each namespace (ex. menu.ts) with the translations.
+ * 
+ * Q: How do I add a new namespace?
+ * A: To add a new namespace, create a new file in each language folder with the translations.
+ *    Then update the `resources` field in the init() call and the CustomTypeOptions interface.
+ */
+
+i18next.init({
+  lng: DEFAULT_LANGUAGE_OVERRIDE ? DEFAULT_LANGUAGE_OVERRIDE : 'en',
+  fallbackLng: 'en',
+  debug: true,
+  resources: {
+    en: {
+      menu: enMenu,
+    },
+    it: {
+      menu: itMenu,
+    }
+  },
+});
+
+// Module declared to make referencing keys in the localization files type-safe.
+declare module 'i18next' {
+  interface CustomTypeOptions {
+    resources: {
+      menu: typeof enMenu;
+    };
+  }
+}
+
+export default i18next;