Import latest app updates from streamline

An updated set of source files and initialization was provided by streamline to
address issues observed during initial testing. These files have been updated in
order to generate a new set of app images.

docker/streamline-src/vendor/symfony/mime/Encoder/EncoderInterface.php

@@ -1,26 +0,0 @@
-<?php
-
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <fabien@symfony.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-namespace Symfony\Component\Mime\Encoder;
-
-/**
- * @author Chris Corbyn
- */
-interface EncoderInterface
-{
-    /**
-     * Encode a given string to produce an encoded string.
-     *
-     * @param int $firstLineOffset if first line needs to be shorter
-     * @param int $maxLineLength   - 0 indicates the default length for this encoding
-     */
-    public function encodeString(string $string, ?string $charset = 'utf-8', int $firstLineOffset = 0, int $maxLineLength = 0): string;
-}