Refactor templates to be more structured

templates/security/login.html.twig

@@ -1,6 +1,6 @@
-{% extends 'base/base.html.twig' %}
+{% extends 'base/single.column.html.twig' %}
 
-{% block title %}Login{% endblock %}
+{% set title %}Login{% endset %}
 
 {% block body %}
     <form action="{{ path('login') }}" method="post">
@@ -12,7 +12,6 @@
                 You are already logged in as {{ app.user }}, <a href="{{ path('logout') }}">Logout</a>
             </div>
         {% endif %}
-        <h1 class="h3 mb-3 font-weight-normal">Please login</h1>
         <label for="inputUsername">Username</label>
         <input type="text" value="{{ last_username }}" name="_username" id="inputUsername" class="form-control" required
                autofocus>

templates/security/register.html.twig

@@ -1,8 +1,7 @@
-{% extends 'base/base.html.twig' %}
+{% extends 'base/single.column.html.twig' %}
 
-{% block title %}Register{% endblock %}
+{% set title %}Register{% endset %}
 
 {% block body %}
-    <h1 class="h3 mb-3 font-weight-normal">Register new user</h1>
     {{ form(registrationForm) }}
 {% endblock %}