Make en the default locale in testing

Fixes #113

blueprints/@kaliber5/k5-ember-boilerplate/files/__root__/pods/application/route.ts

@@ -1,12 +1,17 @@
 import Route from '@ember/routing/route';
 import { inject as service } from '@ember/service';
 import Intl from 'ember-intl/services/intl';
+import { isTesting, macroCondition } from '@embroider/macros';
 
 export default class ApplicationRoute extends Route {
   @service intl!: Intl;
 
-  beforeModel(): void | Promise<unknown> {
-    this.intl.setLocale('de-de');
+  queryParams = {
+    locale: { refreshModel: true },
+  };
+
+  model({ locale = macroCondition(isTesting()) ? 'en-us' : 'de-de' }: { locale: string }): void {
+    this.intl.setLocale(locale);
   }
 
   afterModel(): void {

blueprints/@kaliber5/k5-ember-boilerplate/files/tests/acceptance/errors.feature

@@ -6,9 +6,9 @@ Scenario: Page not found when visiting [URL]
 
   When I visit URL "[URL]"
   Then there should be an Error-Message
-  And the Title in the Error-Message should have text "Etwas ist schiefgelaufen!"
-  And the Description in the Error-Message should have text "Seite wurde nicht gefunden."
-  And the Link in the Error-Message should have text "zurück zur Startseite"
+  And the Title in the Error-Message should have text "Something went wrong!"
+  And the Description in the Error-Message should have text "Page not found."
+  And the Link in the Error-Message should have text "Back to homepage"
   And the Link in the Error-Message should have HTML attr "href" with value "/"
 
 Where:

blueprints/@kaliber5/k5-ember-boilerplate/index.js

@@ -22,6 +22,7 @@ module.exports = {
   async afterInstall(/* options */) {
     await this.addAddonsToProject({
       packages: [
+        { name: '@embroider/macros' },
         { name: 'ember-bootstrap' },
         { name: 'ember-cli-dotenv' },
         { name: 'ember-cli-favicon' },