performance improvements (#2329)

* remove work from constructor
* refactor twig extensions
* upgrade theme
* replace sub-request with direct template rendering

src/Twig/Runtime/EncoreExtension.php

@@ -0,0 +1,56 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Twig\Runtime;
+
+use Psr\Container\ContainerInterface;
+use Symfony\Contracts\Service\ServiceSubscriberInterface;
+use Symfony\WebpackEncoreBundle\Asset\EntrypointLookupInterface;
+use Twig\Extension\RuntimeExtensionInterface;
+
+final class EncoreExtension implements RuntimeExtensionInterface, ServiceSubscriberInterface
+{
+    /**
+     * @var string
+     */
+    private $publicDir;
+    /**
+     * @var ContainerInterface
+     */
+    private $container;
+
+    public function __construct(ContainerInterface $container, string $projectDirectory)
+    {
+        $this->container = $container;
+        $this->publicDir = $projectDirectory . '/public';
+    }
+
+    public static function getSubscribedServices()
+    {
+        return [
+            EntrypointLookupInterface::class,
+        ];
+    }
+
+    public function getEncoreEntryCssSource(string $packageName): string
+    {
+        $lookup = $this->container->get(EntrypointLookupInterface::class);
+        $files = $lookup->getCssFiles($packageName);
+
+        $source = '';
+
+        foreach ($files as $file) {
+            $source .= file_get_contents($this->publicDir . '/' . $file);
+        }
+
+        $lookup->reset();
+
+        return $source;
+    }
+}