feat: Add FontAwesome thumbnail badges

layouts/partials/list-item-thumbnail.html

@@ -1,3 +1,11 @@
+{{ with .Param "fa-thumbnail" }}
+  <div class="thumb-icon-wrapper mb-3">
+    <span class="badge thumb-icon-badge rounded-pill bg-primary py-4 px-5">
+      <i class="fa-fw {{ . }}"></i>
+    </span>
+  </div>
+{{ end }}
+
 {{/* Thumbnail images should be stored as 'thumbnail'.* in the page bundle, but
   historically they might have been referenced as 'thumbnail' in the front
   matter, or (even more historically) as 'cardImage'. Use scratch to