Implement email verification feature, add registration form, and update user entity for verification status

templates/backoffice/base.html.twig

@@ -28,7 +28,14 @@
 {% endblock nav %}
 <main>
     <div class="container">
-        {# {% include "messages.html" %} #}
+        {% for label, messages in app.flashes() %}
+            {% for message in messages %}
+                <div class="alert alert-{{ label }} alert-dismissible " role="alert">
+                    {{ message }}
+                    <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
+                </div>
+            {% endfor %}
+        {% endfor %}
         {% block body %}
         {% endblock body %}
     </div>