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/barryvdh/laravel-snappy/src/ImageWrapper.php

@@ -0,0 +1,199 @@
+<?php namespace Barryvdh\Snappy;
+
+use Illuminate\Http\Response;
+use Knp\Snappy\Image as SnappyImage;
+use Illuminate\Support\Facades\View;
+use Symfony\Component\HttpFoundation\StreamedResponse;
+
+/**
+ * A Laravel wrapper for SnappyImage
+ *
+ * @package laravel-snappy
+ * @author Killian Blais
+ */
+class ImageWrapper {
+
+	/**
+     * @var \Knp\Snappy\Image
+     */
+    protected $snappy;
+
+    /**
+     * @var array
+     */
+    protected $options = array();
+
+
+    /**
+     * @param \Knp\Snappy\Image $snappy
+     */
+    public function __construct(SnappyImage $snappy)
+    {
+       $this->snappy = $snappy;
+    }
+
+    /**
+     * Get the Snappy instance.
+     *
+     * @return \Knp\Snappy\Image
+     */
+    public function snappy()
+    {
+     return $this->snappy;
+    }
+
+    public function setOption($name, $value)
+    {
+        $this->snappy->setOption($name, $value);
+        return $this;
+    }
+
+    public function setOptions($options)
+    {
+        $this->snappy->setOptions($options);
+        return $this;
+    }
+
+    /**
+     * Load a HTML string
+     *
+     * @param string $string
+     * @return static
+     */
+    public function loadHTML($string)
+    {
+        $this->html = (string) $string;
+        $this->file = null;
+        return $this;
+    }
+
+    /**
+     * Load a HTML file
+     *
+     * @param string $file
+     * @return static
+     */
+    public function loadFile($file)
+    {
+        $this->html = null;
+        $this->file = $file;
+        return $this;
+    }
+
+	public function loadView($view, $data = array(), $mergeData = array())
+    {
+        $this->html = View::make($view, $data, $mergeData)->render();
+        $this->file = null;
+        return $this;
+    }
+
+    /**
+     * Output the PDF as a string.
+     *
+     * @return string The rendered PDF as string
+     * @throws \InvalidArgumentException
+     */
+    public function output()
+    {
+        if ($this->html)
+        {
+            return $this->snappy->getOutputFromHtml($this->html, $this->options);
+        }
+
+        if ($this->file)
+        {
+            return $this->snappy->getOutput($this->file, $this->options);
+        }
+
+        throw new \InvalidArgumentException('Image Generator requires a html or file in order to produce output.');
+    }
+
+    /**
+     * Save the image to a file
+     *
+     * @param $filename
+     * @return static
+     */
+    public function save($filename, $overwrite = false)
+    {
+
+        if ($this->html)
+        {
+            $this->snappy->generateFromHtml($this->html, $filename, $this->options, $overwrite);
+        }
+        elseif ($this->file)
+        {
+            $this->snappy->generate($this->file, $filename, $this->options, $overwrite);
+        }
+
+        return $this;
+    }
+
+    /**
+     * Make the image downloadable by the user
+     *
+     * @param string $filename
+     * @return \Symfony\Component\HttpFoundation\Response
+     */
+    public function download($filename = 'image.jpg')
+    {
+        return new Response($this->output(), 200, array(
+            'Content-Type' => 'image/jpeg',
+            'Content-Disposition' =>  'attachment; filename="'.$filename.'"'
+        ));
+    }
+
+    /**
+     * Return a response with the image to show in the browser
+     *
+     * @param string $filename
+     * @return \Illuminate\Http\Response
+     */
+    public function inline($filename = 'image.jpg')
+    {
+        return new Response($this->output(), 200, array(
+            'Content-Type' => 'image/jpeg',
+            'Content-Disposition' => 'inline; filename="'.$filename.'"',
+        ));
+    }
+    
+    /**
+     * Return a response with the image to show in the browser
+     *
+     * @deprecated Use inline() instead
+     * @param string $filename
+     * @return \Symfony\Component\HttpFoundation\Response
+     */
+    public function stream($filename = 'image.jpg')
+    {
+        return new StreamedResponse(function() {
+            echo $this->output();
+        }, 200, array(
+            'Content-Type' => 'image/jpeg',
+            'Content-Disposition' => 'inline; filename="'.$filename.'"',
+        ));
+    }
+
+    /**
+     * Call Snappy instance.
+     *
+     * Also shortcut's
+     * ->html => loadHtml
+     * ->view => loadView
+     * ->file => loadFile
+     *
+     * @param string $name
+     * @param array $arguments
+     * @return mixed
+     */
+    public function __call($name, array $arguments)
+    {
+        $method = 'load' . ucfirst($name);
+        if (method_exists($this, $method))
+        {
+            return call_user_func_array(array($this, $method), $arguments);
+        }
+
+        return call_user_func_array (array($this->snappy, $name), $arguments);
+    }
+}