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/polyfill-php80/Resources/stubs/Attribute.php

@@ -0,0 +1,22 @@
+<?php
+
+#[Attribute(Attribute::TARGET_CLASS)]
+final class Attribute
+{
+    public const TARGET_CLASS = 1;
+    public const TARGET_FUNCTION = 2;
+    public const TARGET_METHOD = 4;
+    public const TARGET_PROPERTY = 8;
+    public const TARGET_CLASS_CONSTANT = 16;
+    public const TARGET_PARAMETER = 32;
+    public const TARGET_ALL = 63;
+    public const IS_REPEATABLE = 64;
+
+    /** @var int */
+    public $flags;
+
+    public function __construct(int $flags = self::TARGET_ALL)
+    {
+        $this->flags = $flags;
+    }
+}

lib/symfony/polyfill-php80/Resources/stubs/PhpToken.php

@@ -0,0 +1,7 @@
+<?php
+
+if (\PHP_VERSION_ID < 80000 && \extension_loaded('tokenizer')) {
+    class PhpToken extends Symfony\Polyfill\Php80\PhpToken
+    {
+    }
+}

lib/symfony/polyfill-php80/Resources/stubs/Stringable.php

@@ -0,0 +1,11 @@
+<?php
+
+if (\PHP_VERSION_ID < 80000) {
+    interface Stringable
+    {
+        /**
+         * @return string
+         */
+        public function __toString();
+    }
+}

lib/symfony/polyfill-php80/Resources/stubs/UnhandledMatchError.php

@@ -0,0 +1,7 @@
+<?php
+
+if (\PHP_VERSION_ID < 80000) {
+    class UnhandledMatchError extends Error
+    {
+    }
+}

lib/symfony/polyfill-php80/Resources/stubs/ValueError.php

@@ -0,0 +1,7 @@
+<?php
+
+if (\PHP_VERSION_ID < 80000) {
+    class ValueError extends Error
+    {
+    }
+}