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/league/commonmark/src/Normalizer/SlugNormalizer.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the league/commonmark package.
+ *
+ * (c) Colin O'Dell <colinodell@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace League\CommonMark\Normalizer;
+
+use League\Config\ConfigurationAwareInterface;
+use League\Config\ConfigurationInterface;
+
+/**
+ * Creates URL-friendly strings based on the given string input
+ */
+final class SlugNormalizer implements TextNormalizerInterface, ConfigurationAwareInterface
+{
+    /** @psalm-allow-private-mutation */
+    private int $defaultMaxLength = 255;
+
+    public function setConfiguration(ConfigurationInterface $configuration): void
+    {
+        $this->defaultMaxLength = $configuration->get('slug_normalizer/max_length');
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @psalm-immutable
+     */
+    public function normalize(string $text, array $context = []): string
+    {
+        // Add any requested prefix
+        $slug = ($context['prefix'] ?? '') . $text;
+        // Trim whitespace
+        $slug = \trim($slug);
+        // Convert to lowercase
+        $slug = \mb_strtolower($slug, 'UTF-8');
+        // Try replacing whitespace with a dash
+        $slug = \preg_replace('/\s+/u', '-', $slug) ?? $slug;
+        // Try removing characters other than letters, numbers, and marks.
+        $slug = \preg_replace('/[^\p{L}\p{Nd}\p{Nl}\p{M}-]+/u', '', $slug) ?? $slug;
+        // Trim to requested length if given
+        if ($length = $context['length'] ?? $this->defaultMaxLength) {
+            $slug = \mb_substr($slug, 0, $length, 'UTF-8');
+        }
+
+        return $slug;
+    }
+}

docker/streamline-src/vendor/league/commonmark/src/Normalizer/TextNormalizer.php

@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * This file is part of the league/commonmark package.
+ *
+ * (c) Colin O'Dell <colinodell@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace League\CommonMark\Normalizer;
+
+/***
+ * Normalize text input using the steps given by the CommonMark spec to normalize labels
+ *
+ * @see https://spec.commonmark.org/0.29/#matches
+ *
+ * @psalm-immutable
+ */
+final class TextNormalizer implements TextNormalizerInterface
+{
+    /**
+     * {@inheritDoc}
+     *
+     * @psalm-pure
+     */
+    public function normalize(string $text, array $context = []): string
+    {
+        // Collapse internal whitespace to single space and remove
+        // leading/trailing whitespace
+        $text = \preg_replace('/[ \t\r\n]+/', ' ', \trim($text));
+        \assert(\is_string($text));
+
+        return \mb_convert_case($text, \MB_CASE_FOLD, 'UTF-8');
+    }
+}

docker/streamline-src/vendor/league/commonmark/src/Normalizer/TextNormalizerInterface.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the league/commonmark package.
+ *
+ * (c) Colin O'Dell <colinodell@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace League\CommonMark\Normalizer;
+
+/**
+ * Creates a normalized version of the given input text
+ */
+interface TextNormalizerInterface
+{
+    /**
+     * @param string               $text    The text to normalize
+     * @param array<string, mixed> $context Additional context about the text being normalized (optional)
+     *
+     * $context may include (but is not required to include) the following:
+     *   - `prefix` - A string prefix to prepend to each normalized result
+     *   - `length` - The requested maximum length
+     *   - `node` - The node we're normalizing text for
+     *
+     * Implementations do not have to use or respect any information within that $context
+     */
+    public function normalize(string $text, array $context = []): string;
+}

docker/streamline-src/vendor/league/commonmark/src/Normalizer/UniqueSlugNormalizer.php

@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the league/commonmark package.
+ *
+ * (c) Colin O'Dell <colinodell@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace League\CommonMark\Normalizer;
+
+// phpcs:disable Squiz.Strings.DoubleQuoteUsage.ContainsVar
+final class UniqueSlugNormalizer implements UniqueSlugNormalizerInterface
+{
+    private TextNormalizerInterface $innerNormalizer;
+    /** @var array<string, bool> */
+    private array $alreadyUsed = [];
+
+    public function __construct(TextNormalizerInterface $innerNormalizer)
+    {
+        $this->innerNormalizer = $innerNormalizer;
+    }
+
+    public function clearHistory(): void
+    {
+        $this->alreadyUsed = [];
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @psalm-allow-private-mutation
+     */
+    public function normalize(string $text, array $context = []): string
+    {
+        $normalized = $this->innerNormalizer->normalize($text, $context);
+
+        // If it's not unique, add an incremental number to the end until we get a unique version
+        if (\array_key_exists($normalized, $this->alreadyUsed)) {
+            $suffix = 0;
+            do {
+                ++$suffix;
+            } while (\array_key_exists("$normalized-$suffix", $this->alreadyUsed));
+
+            $normalized = "$normalized-$suffix";
+        }
+
+        $this->alreadyUsed[$normalized] = true;
+
+        return $normalized;
+    }
+}

docker/streamline-src/vendor/league/commonmark/src/Normalizer/UniqueSlugNormalizerInterface.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the league/commonmark package.
+ *
+ * (c) Colin O'Dell <colinodell@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace League\CommonMark\Normalizer;
+
+interface UniqueSlugNormalizerInterface extends TextNormalizerInterface
+{
+    public const DISABLED        = false;
+    public const PER_ENVIRONMENT = 'environment';
+    public const PER_DOCUMENT    = 'document';
+
+    /**
+     * Called by the Environment whenever the configured scope changes
+     *
+     * Currently, this will only be called PER_DOCUMENT.
+     */
+    public function clearHistory(): void;
+}