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/Dumper/ContextualizedDumper.php

@@ -0,0 +1,43 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\VarDumper\Dumper;
+
+use Symfony\Component\VarDumper\Cloner\Data;
+use Symfony\Component\VarDumper\Dumper\ContextProvider\ContextProviderInterface;
+
+/**
+ * @author Kévin Thérage <therage.kevin@gmail.com>
+ */
+class ContextualizedDumper implements DataDumperInterface
+{
+    private $wrappedDumper;
+    private $contextProviders;
+
+    /**
+     * @param ContextProviderInterface[] $contextProviders
+     */
+    public function __construct(DataDumperInterface $wrappedDumper, array $contextProviders)
+    {
+        $this->wrappedDumper = $wrappedDumper;
+        $this->contextProviders = $contextProviders;
+    }
+
+    public function dump(Data $data)
+    {
+        $context = [];
+        foreach ($this->contextProviders as $contextProvider) {
+            $context[\get_class($contextProvider)] = $contextProvider->getContext();
+        }
+
+        $this->wrappedDumper->dump($data->withContext($context));
+    }
+}