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/hamcrest/hamcrest-php/generator/parts/file_header.txt

@@ -0,0 +1,7 @@
+<?php
+
+/*
+ Copyright (c) 2009-2010 hamcrest.org
+ */
+
+// This file is generated from the static method @factory doctags.

docker/streamline-src/vendor/hamcrest/hamcrest-php/generator/parts/functions_header.txt

@@ -0,0 +1,24 @@
+
+if (!function_exists('assertThat')) {
+    /**
+     * Make an assertion and throw {@link Hamcrest_AssertionError} if it fails.
+     *
+     * Example:
+     * <pre>
+     * //With an identifier
+     * assertThat("assertion identifier", $apple->flavour(), equalTo("tasty"));
+     * //Without an identifier
+     * assertThat($apple->flavour(), equalTo("tasty"));
+     * //Evaluating a boolean expression
+     * assertThat("some error", $a > $b);
+     * </pre>
+     */
+    function assertThat()
+    {
+        $args = func_get_args();
+        call_user_func_array(
+            array('Hamcrest\MatcherAssert', 'assertThat'),
+            $args
+        );
+    }
+}

docker/streamline-src/vendor/hamcrest/hamcrest-php/generator/parts/matchers_footer.txt

@@ -0,0 +1 @@
+}

docker/streamline-src/vendor/hamcrest/hamcrest-php/generator/parts/matchers_header.txt

@@ -0,0 +1,7 @@
+
+
+/**
+ * A series of static factories for all hamcrest matchers.
+ */
+class Matchers
+{

docker/streamline-src/vendor/hamcrest/hamcrest-php/generator/parts/matchers_imports.txt

@@ -0,0 +1,2 @@
+
+namespace Hamcrest;