add: php composer management

vendor/composer/installers/src/Composer/Installers/RedaxoInstaller.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace Composer\Installers;
+
+class RedaxoInstaller extends BaseInstaller
+{
+    /** @var array<string, string> */
+    protected $locations = array(
+        'addon'          => 'redaxo/include/addons/{$name}/',
+        'bestyle-plugin' => 'redaxo/include/addons/be_style/plugins/{$name}/'
+    );
+}