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/flysystem/src/FilesystemWriter.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace League\Flysystem;
+
+interface FilesystemWriter
+{
+    /**
+     * @throws UnableToWriteFile
+     * @throws FilesystemException
+     */
+    public function write(string $location, string $contents, array $config = []): void;
+
+    /**
+     * @param mixed $contents
+     *
+     * @throws UnableToWriteFile
+     * @throws FilesystemException
+     */
+    public function writeStream(string $location, $contents, array $config = []): void;
+
+    /**
+     * @throws UnableToSetVisibility
+     * @throws FilesystemException
+     */
+    public function setVisibility(string $path, string $visibility): void;
+
+    /**
+     * @throws UnableToDeleteFile
+     * @throws FilesystemException
+     */
+    public function delete(string $location): void;
+
+    /**
+     * @throws UnableToDeleteDirectory
+     * @throws FilesystemException
+     */
+    public function deleteDirectory(string $location): void;
+
+    /**
+     * @throws UnableToCreateDirectory
+     * @throws FilesystemException
+     */
+    public function createDirectory(string $location, array $config = []): void;
+
+    /**
+     * @throws UnableToMoveFile
+     * @throws FilesystemException
+     */
+    public function move(string $source, string $destination, array $config = []): void;
+
+    /**
+     * @throws UnableToCopyFile
+     * @throws FilesystemException
+     */
+    public function copy(string $source, string $destination, array $config = []): void;
+}