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/phpunit/php-file-iterator/src/Facade.php

@@ -0,0 +1,52 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of phpunit/php-file-iterator.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace SebastianBergmann\FileIterator;
+
+use function array_unique;
+use function assert;
+use function sort;
+use SplFileInfo;
+
+/**
+ * @no-named-arguments Parameter names are not covered by the backward compatibility promise for PHPUnit
+ */
+final class Facade
+{
+    /**
+     * @psalm-param list<non-empty-string>|non-empty-string $paths
+     * @psalm-param list<non-empty-string>|string $suffixes
+     * @psalm-param list<non-empty-string>|string $prefixes
+     * @psalm-param list<non-empty-string> $exclude
+     *
+     * @psalm-return list<non-empty-string>
+     */
+    public function getFilesAsArray(array|string $paths, array|string $suffixes = '', array|string $prefixes = '', array $exclude = []): array
+    {
+        $iterator = (new Factory)->getFileIterator($paths, $suffixes, $prefixes, $exclude);
+
+        $files = [];
+
+        foreach ($iterator as $file) {
+            assert($file instanceof SplFileInfo);
+
+            $file = $file->getRealPath();
+
+            if ($file) {
+                $files[] = $file;
+            }
+        }
+
+        $files = array_unique($files);
+
+        sort($files);
+
+        return $files;
+    }
+}