migration symfony 5 4 (#300)

* symfony 5.4 (diff dev)

* symfony 5.4 (working)

* symfony 5.4 (update autoload)

* symfony 5.4 (remove swiftmailer mailer implementation)

* symfony 5.4 (php doc and split Global accessor class)


### Impacted packages:

composer require php:">=7.2.5 <8.0.0" symfony/console:5.4.* symfony/dotenv:5.4.* symfony/framework-bundle:5.4.* symfony/twig-bundle:5.4.* symfony/yaml:5.4.* --update-with-dependencies

composer require symfony/stopwatch:5.4.* symfony/web-profiler-bundle:5.4.* --dev --update-with-dependencies

lib/symfony/var-dumper/Resources/js/htmlDescriptor.js

@@ -0,0 +1,10 @@
+document.addEventListener('DOMContentLoaded', function() {
+  let prev = null;
+  Array.from(document.getElementsByTagName('article')).reverse().forEach(function (article) {
+    const dedupId = article.dataset.dedupId;
+    if (dedupId === prev) {
+      article.getElementsByTagName('header')[0].classList.add('hidden');
+    }
+    prev = dedupId;
+  });
+});