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/tests/Hamcrest/FeatureMatcherTest.php

@@ -0,0 +1,73 @@
+<?php
+namespace Hamcrest;
+
+class Thingy
+{
+    private $_result;
+    public function __construct($result)
+    {
+        $this->_result = $result;
+    }
+    public function getResult()
+    {
+        return $this->_result;
+    }
+}
+
+/* Test-specific subclass only */
+class ResultMatcher extends \Hamcrest\FeatureMatcher
+{
+    public function __construct()
+    {
+        parent::__construct(self::TYPE_ANY, null, equalTo('bar'), 'Thingy with result', 'result');
+    }
+    public function featureValueOf($actual)
+    {
+        if ($actual instanceof \Hamcrest\Thingy) {
+            return $actual->getResult();
+        }
+    }
+}
+
+class FeatureMatcherTest extends \Hamcrest\AbstractMatcherTest
+{
+
+    private $_resultMatcher;
+
+    protected function setUp()
+    {
+        $this->_resultMatcher = $this->_resultMatcher();
+    }
+
+    protected function createMatcher()
+    {
+        return $this->_resultMatcher();
+    }
+
+    public function testMatchesPartOfAnObject()
+    {
+        $this->assertMatches($this->_resultMatcher, new \Hamcrest\Thingy('bar'), 'feature');
+        $this->assertDescription('Thingy with result "bar"', $this->_resultMatcher);
+    }
+
+    public function testMismatchesPartOfAnObject()
+    {
+        $this->assertMismatchDescription(
+            'result was "foo"',
+            $this->_resultMatcher,
+            new \Hamcrest\Thingy('foo')
+        );
+    }
+
+    public function testDoesNotGenerateNoticesForNull()
+    {
+        $this->assertMismatchDescription('result was null', $this->_resultMatcher, null);
+    }
+
+    // -- Creation Methods
+
+    private function _resultMatcher()
+    {
+        return new \Hamcrest\ResultMatcher();
+    }
+}