Build modified streamline images

The official image from streamline does not currently work for the arm64
platform. As a temporary measure, the source code and docker build scripts
have been lifted from the official images and are used to build locally.

Some additional modifications are made to reduce overall image size, these
are documented in docker/README.md

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

@@ -0,0 +1,66 @@
+<?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\Component\EventDispatcher;
+
+use Symfony\Contracts\EventDispatcher\EventDispatcherInterface as ContractsEventDispatcherInterface;
+
+/**
+ * The EventDispatcherInterface is the central point of Symfony's event listener system.
+ * Listeners are registered on the manager and events are dispatched through the
+ * manager.
+ *
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ */
+interface EventDispatcherInterface extends ContractsEventDispatcherInterface
+{
+    /**
+     * Adds an event listener that listens on the specified events.
+     *
+     * @param int $priority The higher this value, the earlier an event
+     *                      listener will be triggered in the chain (defaults to 0)
+     */
+    public function addListener(string $eventName, callable $listener, int $priority = 0): void;
+
+    /**
+     * Adds an event subscriber.
+     *
+     * The subscriber is asked for all the events it is
+     * interested in and added as a listener for these events.
+     */
+    public function addSubscriber(EventSubscriberInterface $subscriber): void;
+
+    /**
+     * Removes an event listener from the specified events.
+     */
+    public function removeListener(string $eventName, callable $listener): void;
+
+    public function removeSubscriber(EventSubscriberInterface $subscriber): void;
+
+    /**
+     * Gets the listeners of a specific event or all listeners sorted by descending priority.
+     *
+     * @return array<callable[]|callable>
+     */
+    public function getListeners(?string $eventName = null): array;
+
+    /**
+     * Gets the listener priority for a specific event.
+     *
+     * Returns null if the event or the listener does not exist.
+     */
+    public function getListenerPriority(string $eventName, callable $listener): ?int;
+
+    /**
+     * Checks whether an event has any registered listeners.
+     */
+    public function hasListeners(?string $eventName = null): bool;
+}