fix(homepage): use WEBAPP_NAME variable environment

webapp/config/packages/twig.yaml

 twig:
     file_name_pattern: '*.twig'
+    globals:
+        app_name: '%env(WEBAPP_NAME)%'
 
 when@test:
     twig:

webapp/templates/home.html.twig

 {% extends 'app_base.html.twig' %}
-{% block title %}Comptoir du Libre{% endblock %}
+{% block title %}{{ app_name }}{% endblock %}
 
 {% block body %}
     <style>
@@ -8,6 +8,6 @@
     </style>
 
     <div class="example-wrapper">
-        <h1>Comptoir du Libre</h1>
+        <h1>{{ app_name }}</h1>
     </div>
 {% endblock %}