feat(frontend): kosmetische verbeteringen & i18n in de callback-pagina

frontend/src/i18n/locale/de.json

@@ -75,5 +75,7 @@
     "sent": "sent",
     "failed": "gescheitert",
     "wrong": "etwas ist schief gelaufen",
-    "created": "erstellt"
+    "created": "erstellt",
+    "callbackLoading": "Sie werden angemeldet...",
+    "loginUnexpectedError": "Anmeldung fehlgeschlagen"
 }

frontend/src/i18n/locale/en.json

@@ -75,5 +75,7 @@
     "sent": "sent",
     "failed": "failed",
     "wrong": "something went wrong",
-    "created": "created"
+    "created": "created",
+    "callbackLoading": "You are being logged in...",
+    "loginUnexpectedError": "Login failed"
 }

frontend/src/i18n/locale/fr.json

@@ -75,5 +75,7 @@
     "sent": "envoyé",
     "failed": "échoué",
     "wrong": "quelque chose n'a pas fonctionné",
-    "created": "créé"
+    "created": "créé",
+    "callbackLoading": "Vous serez connecté...",
+    "loginUnexpectedError": "La connexion a échoué"
 }

frontend/src/i18n/locale/nl.json

@@ -75,5 +75,7 @@
     "sent": "verzonden",
     "failed": "mislukt",
     "wrong": "er ging iets verkeerd",
-    "created": "gecreëerd"
+    "created": "gecreëerd",
+    "callbackLoading": "Je wordt ingelogd...",
+    "loginUnexpectedError": "Inloggen mislukt"
 }