Import latest app updates from streamline

An updated set of source files and initialization was provided by streamline to
address issues observed during initial testing. These files have been updated in
order to generate a new set of app images.

docker/streamline-src/vendor/symfony/event-dispatcher-contracts/EventDispatcherInterface.php

@@ -1,33 +0,0 @@
-<?php
-
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <fabien@symfony.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-namespace Symfony\Contracts\EventDispatcher;
-
-use Psr\EventDispatcher\EventDispatcherInterface as PsrEventDispatcherInterface;
-
-/**
- * Allows providing hooks on domain-specific lifecycles by dispatching events.
- */
-interface EventDispatcherInterface extends PsrEventDispatcherInterface
-{
-    /**
-     * Dispatches an event to all registered listeners.
-     *
-     * @template T of object
-     *
-     * @param T           $event     The event to pass to the event handlers/listeners
-     * @param string|null $eventName The name of the event to dispatch. If not supplied,
-     *                               the class of $event should be used instead.
-     *
-     * @return T The passed $event MUST be returned
-     */
-    public function dispatch(object $event, string $eventName = null): object;
-}