Introduce markup to event page for event title presentation

added 'wrapper' classes to ensure the placement of the title and added inline comments to indicate where other elements should be in the future.

DDFFORM-15.

web/themes/custom/novel/templates/layout/node--event--full.html.twig

@@ -0,0 +1,16 @@
+<article class="event-page">
+  <header class="event-header">
+    <section class="event-header__content">
+      <div class="event-header__extra-padding">
+        <!-- Tag -->
+        <!-- dates -->
+        <h1 class="event-header__title">{{ label }}</h1>
+      </div>
+      <!-- button -->
+    </section>
+    <section class="event-header__visual">
+      <!-- image -->
+    </section>
+  </header>
+  {{ content }}
+</article>