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/routing/RouterInterface.php

@@ -0,0 +1,35 @@
+<?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\Routing;
+
+use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
+use Symfony\Component\Routing\Matcher\UrlMatcherInterface;
+
+/**
+ * RouterInterface is the interface that all Router classes must implement.
+ *
+ * This interface is the concatenation of UrlMatcherInterface and UrlGeneratorInterface.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+interface RouterInterface extends UrlMatcherInterface, UrlGeneratorInterface
+{
+    /**
+     * Gets the RouteCollection instance associated with this Router.
+     *
+     * WARNING: This method should never be used at runtime as it is SLOW.
+     *          You might use it in a cache warmer though.
+     *
+     * @return RouteCollection
+     */
+    public function getRouteCollection();
+}