Group FAQs by a topic relation, ordered; drop unused FAQ teaser

Elternbeirat.Web/Features/Faqs/FaqList.razor

@@ -17,7 +17,7 @@ else
     @foreach (var group in _groups)
     {
         <section class="faq-topic">
-            <h2>@group.Key</h2>
+            <h2>@group.Key.Title</h2>
             @foreach (var faq in group)
             {
                 <details class="faq-item">