Add authors and date

Ref: https://gitlab.com/agaric/sites/agaric-coop/-/issues/239

agaric/templates/field/field--field-title.html.twig

@@ -46,4 +46,9 @@
     })
   %}
   <h1{{ item.attributes }}>{{ item.content}} </h1>
+
+  {% if authors is not empty %}
+    <p class="byline is-mono">Written by {{ authors }}</p>
+    <p class="byline is-mono">Posted on <time class="dt-published" datetime="{{ iso_datetime }}">{{ date }}</time></p>
+  {% endif %}
 {% endfor %}