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)

server/locale.js

@@ -0,0 +1,26 @@
+const fs = require('fs');
+const path = require('path');
+const { FluentBundle } = require('fluent');
+const localesPath = path.resolve(__dirname, '../public/locales');
+const locales = fs.readdirSync(localesPath);
+
+function makeBundle(locale) {
+  const bundle = new FluentBundle(locale, { useIsolating: false });
+  bundle.addMessages(
+    fs.readFileSync(path.resolve(localesPath, locale, 'send.ftl'))
+  );
+  return [locale, bundle];
+}
+
+const bundles = new Map(locales.map(makeBundle));
+
+module.exports = function getTranslator(locale) {
+  const defaultBundle = bundles.get('en-US');
+  const bundle = bundles.get(locale) || defaultBundle;
+  return function(id, data) {
+    if (bundle.hasMessage(id)) {
+      return bundle.format(bundle.getMessage(id), data);
+    }
+    return defaultBundle.format(defaultBundle.getMessage(id), data);
+  };
+};