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/nette/utils/src/Utils/ArrayHash.php

@@ -0,0 +1,106 @@
+<?php
+
+/**
+ * This file is part of the Nette Framework (https://nette.org)
+ * Copyright (c) 2004 David Grudl (https://davidgrudl.com)
+ */
+
+declare(strict_types=1);
+
+namespace Nette\Utils;
+
+use Nette;
+
+
+/**
+ * Provides objects to work as array.
+ * @template T
+ * @implements \IteratorAggregate<array-key, T>
+ * @implements \ArrayAccess<array-key, T>
+ */
+class ArrayHash extends \stdClass implements \ArrayAccess, \Countable, \IteratorAggregate
+{
+	/**
+	 * Transforms array to ArrayHash.
+	 * @param  array<T>  $array
+	 */
+	public static function from(array $array, bool $recursive = true): static
+	{
+		$obj = new static;
+		foreach ($array as $key => $value) {
+			$obj->$key = $recursive && is_array($value)
+				? static::from($value)
+				: $value;
+		}
+
+		return $obj;
+	}
+
+
+	/**
+	 * Returns an iterator over all items.
+	 * @return \Iterator<array-key, T>
+	 */
+	public function &getIterator(): \Iterator
+	{
+		foreach ((array) $this as $key => $foo) {
+			yield $key => $this->$key;
+		}
+	}
+
+
+	/**
+	 * Returns items count.
+	 */
+	public function count(): int
+	{
+		return count((array) $this);
+	}
+
+
+	/**
+	 * Replaces or appends a item.
+	 * @param  array-key  $key
+	 * @param  T  $value
+	 */
+	public function offsetSet($key, $value): void
+	{
+		if (!is_scalar($key)) { // prevents null
+			throw new Nette\InvalidArgumentException(sprintf('Key must be either a string or an integer, %s given.', get_debug_type($key)));
+		}
+
+		$this->$key = $value;
+	}
+
+
+	/**
+	 * Returns a item.
+	 * @param  array-key  $key
+	 * @return T
+	 */
+	#[\ReturnTypeWillChange]
+	public function offsetGet($key)
+	{
+		return $this->$key;
+	}
+
+
+	/**
+	 * Determines whether a item exists.
+	 * @param  array-key  $key
+	 */
+	public function offsetExists($key): bool
+	{
+		return isset($this->$key);
+	}
+
+
+	/**
+	 * Removes the element from this list.
+	 * @param  array-key  $key
+	 */
+	public function offsetUnset($key): void
+	{
+		unset($this->$key);
+	}
+}