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/doctrine/dbal/src/LockMode.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Doctrine\DBAL;
+
+/**
+ * Contains all DBAL LockModes.
+ */
+class LockMode
+{
+    public const NONE              = 0;
+    public const OPTIMISTIC        = 1;
+    public const PESSIMISTIC_READ  = 2;
+    public const PESSIMISTIC_WRITE = 4;
+
+    /**
+     * Private constructor. This class cannot be instantiated.
+     *
+     * @codeCoverageIgnore
+     */
+    final private function __construct()
+    {
+    }
+}