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/translation/Util/ArrayConverter.php

@@ -0,0 +1,142 @@
+<?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\Translation\Util;
+
+/**
+ * ArrayConverter generates tree like structure from a message catalogue.
+ * e.g. this
+ *   'foo.bar1' => 'test1',
+ *   'foo.bar2' => 'test2'
+ * converts to follows:
+ *   foo:
+ *     bar1: test1
+ *     bar2: test2.
+ *
+ * @author Gennady Telegin <gtelegin@gmail.com>
+ */
+class ArrayConverter
+{
+    /**
+     * Converts linear messages array to tree-like array.
+     * For example this array('foo.bar' => 'value') will be converted to ['foo' => ['bar' => 'value']].
+     *
+     * @param array $messages Linear messages array
+     */
+    public static function expandToTree(array $messages): array
+    {
+        $tree = [];
+
+        foreach ($messages as $id => $value) {
+            $referenceToElement = &self::getElementByPath($tree, self::getKeyParts($id));
+
+            $referenceToElement = $value;
+
+            unset($referenceToElement);
+        }
+
+        return $tree;
+    }
+
+    private static function &getElementByPath(array &$tree, array $parts): mixed
+    {
+        $elem = &$tree;
+        $parentOfElem = null;
+
+        foreach ($parts as $i => $part) {
+            if (isset($elem[$part]) && \is_string($elem[$part])) {
+                /* Process next case:
+                 *    'foo': 'test1',
+                 *    'foo.bar': 'test2'
+                 *
+                 * $tree['foo'] was string before we found array {bar: test2}.
+                 *  Treat new element as string too, e.g. add $tree['foo.bar'] = 'test2';
+                 */
+                $elem = &$elem[implode('.', \array_slice($parts, $i))];
+                break;
+            }
+
+            $parentOfElem = &$elem;
+            $elem = &$elem[$part];
+        }
+
+        if ($elem && \is_array($elem) && $parentOfElem) {
+            /* Process next case:
+             *    'foo.bar': 'test1'
+             *    'foo': 'test2'
+             *
+             * $tree['foo'] was array = {bar: 'test1'} before we found string constant `foo`.
+             * Cancel treating $tree['foo'] as array and cancel back it expansion,
+             *  e.g. make it $tree['foo.bar'] = 'test1' again.
+             */
+            self::cancelExpand($parentOfElem, $part, $elem);
+        }
+
+        return $elem;
+    }
+
+    private static function cancelExpand(array &$tree, string $prefix, array $node): void
+    {
+        $prefix .= '.';
+
+        foreach ($node as $id => $value) {
+            if (\is_string($value)) {
+                $tree[$prefix.$id] = $value;
+            } else {
+                self::cancelExpand($tree, $prefix.$id, $value);
+            }
+        }
+    }
+
+    /**
+     * @return string[]
+     */
+    private static function getKeyParts(string $key): array
+    {
+        $parts = explode('.', $key);
+        $partsCount = \count($parts);
+
+        $result = [];
+        $buffer = '';
+
+        foreach ($parts as $index => $part) {
+            if (0 === $index && '' === $part) {
+                $buffer = '.';
+
+                continue;
+            }
+
+            if ($index === $partsCount - 1 && '' === $part) {
+                $buffer .= '.';
+                $result[] = $buffer;
+
+                continue;
+            }
+
+            if (isset($parts[$index + 1]) && '' === $parts[$index + 1]) {
+                $buffer .= $part;
+
+                continue;
+            }
+
+            if ($buffer) {
+                $result[] = $buffer.$part;
+                $buffer = '';
+
+                continue;
+            }
+
+            $result[] = $part;
+        }
+
+        return $result;
+    }
+}