Add interface for setup wizards

refs #7163

library/Icinga/Web/Setup/SetupWizard.php

@@ -0,0 +1,25 @@
+<?php
+// {{{ICINGA_LICENSE_HEADER}}}
+// {{{ICINGA_LICENSE_HEADER}}}
+
+namespace Icinga\Web\Setup;
+
+/**
+ * Interface for setup wizards providing an installer and requirements
+ */
+interface SetupWizard
+{
+    /**
+     * Return the installer for this wizard
+     *
+     * @return  Installer
+     */
+    public function getInstaller();
+
+    /**
+     * Return the requirements of this wizard
+     *
+     * @return  Requirements
+     */
+    public function getRequirements();
+}