reimplemented l10n using dynamic import() (#1012)

this should greatly reduce the complexity of the l10n code
and build pipeline and eliminate the most common error
seen in sentry logs (no translate function)

app/locale.js

@@ -0,0 +1,26 @@
+import { FluentBundle } from 'fluent';
+
+function makeBundle(locale, ftl) {
+  const bundle = new FluentBundle(locale, { useIsolating: false });
+  bundle.addMessages(ftl);
+  return bundle;
+}
+
+export async function getTranslator(locale) {
+  const bundles = [];
+  const { default: en } = await import('../public/locales/en-US/send.ftl');
+  if (locale !== 'en-US') {
+    const {
+      default: ftl
+    } = await import(`../public/locales/${locale}/send.ftl`);
+    bundles.push(makeBundle(locale, ftl));
+  }
+  bundles.push(makeBundle('en-US', en));
+  return function(id, data) {
+    for (let bundle of bundles) {
+      if (bundle.hasMessage(id)) {
+        return bundle.format(bundle.getMessage(id), data);
+      }
+    }
+  };
+}