Add more meta-data to blog posts

templates/blog/meta_line.html

 <p class="subtitle is-7 py-2">
   <span title="Veröffentlicht am"><i class="fa-solid fa-calendar-days"></i> <time datetime="{{ post.date }}" property="schema:datePublished">{{ post.date }}</time></span> ·
+  <span title="Anzahl Wörter"><i class="fa-solid fa-ruler"></i> <span property="schema:wordCount">{{ post.word_count }} Wörter</span></span> ·
   <span title="Lesezeit"><i class="fa-solid fa-hourglass-start"></i> {{ post.reading_time }} min</span>
 </p>

templates/blog/post.html

@@ -22,7 +22,7 @@
         <div class="card-image">
           <figure class="image is-4by3">
             {% set image = resize_image(path="@/" ~ post.colocated_path ~ "/" ~ post.extra.depiction.image, width=800, height=600) -%}
-              <img src="{{ image.url }}" alt="{{ post.extra.depiction.alt }}" />
+              <img src="{{ image.url }}" alt="{{ post.extra.depiction.alt }}" property="schema:thumbnailUrl" />
             {% if post.extra.depiction.credits %}
               <figcaption class="p-1 has-text-white has-background-black is-size-7 is-italic">{{ post.extra.depiction.credits }}</figcaption>
             {% endif %}