feat: add footer, header and improve layout

iamkonstantin_web/templates/includes/header.html

@@ -0,0 +1,16 @@
+{% load wagtailcore_tags navigation_tags wagtailuserbar %}
+<header>
+    {# Add this: #}
+    <a href="#main" class="skip-link">Skip to content</a>
+
+    {% get_site_root as site_root %}
+    <nav>
+        <p>
+            <a href="{% pageurl site_root %}">{{ site_root.title }}</a> |
+            {% for menuitem in site_root.get_children.live.in_menu %}
+                <a href="{% pageurl menuitem %}">{{ menuitem.title }}</a>{% if not forloop.last %} | {% endif %}
+            {% endfor %}
+        </p>
+    </nav>
+    {% wagtailuserbar "top-right" %}
+</header>