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/dependency-injection/Compiler/ServiceReferenceGraphNode.php

@@ -32,7 +32,7 @@ class ServiceReferenceGraphNode
      * @param string $id    The node identifier
      * @param mixed  $value The node value
      */
-    public function __construct($id, $value)
+    public function __construct(string $id, $value)
     {
         $this->id = $id;
         $this->value = $value;
@@ -51,7 +51,7 @@ class ServiceReferenceGraphNode
     /**
      * Checks if the value of this node is an Alias.
      *
-     * @return bool True if the value is an Alias instance
+     * @return bool
      */
     public function isAlias()
     {
@@ -61,7 +61,7 @@ class ServiceReferenceGraphNode
     /**
      * Checks if the value of this node is a Definition.
      *
-     * @return bool True if the value is a Definition instance
+     * @return bool
      */
     public function isDefinition()
     {
@@ -101,7 +101,7 @@ class ServiceReferenceGraphNode
     /**
      * Returns the value of this Node.
      *
-     * @return mixed The value
+     * @return mixed
      */
     public function getValue()
     {