Major Refactoring (will need some cleanup)

This refactors the plugin from one mega syntax file into multiple
classes.

The plugin now focuses on one usecase: listing files that are external
to the wiki and making them downloadable. All other usecases have been
dropped. Also a bunch of other options have been dropped.

A new dispatcher makes it possible to deliver files without the need to
have the webserver pointing at them.

file.php

@@ -0,0 +1,40 @@
+<?php
+
+use dokuwiki\plugin\filelist\Path;
+
+if (!defined('DOKU_INC')) define('DOKU_INC', __DIR__ . '/../../../');
+if (!defined('NOSESSION')) define('NOSESSION', true); // we do not use a session or authentication here (better caching)
+if (!defined('DOKU_DISABLE_GZIP_OUTPUT')) define('DOKU_DISABLE_GZIP_OUTPUT', 1); // we gzip ourself here
+require_once(DOKU_INC . 'inc/init.php');
+
+global $INPUT;
+
+$syntax = plugin_load('syntax', 'filelist');
+if (!$syntax) die('plugin disabled?');
+
+$pathUtil = new Path($syntax->getConf('paths'));
+$path = $INPUT->str('root') . $INPUT->str('file');
+
+try {
+    $pathInfo = $pathUtil->getPathInfo($path, false);
+    if (!is_readable($pathInfo['path'])) {
+        header('Content-Type: text/plain');
+        http_status(404);
+        echo 'Path not readable: ' . $pathInfo['path'];
+        exit;
+    }
+    [$ext, $mime, $download] = mimetype($pathInfo['path'], false);
+    $basename = basename($pathInfo['path']);
+    header('Content-Type: ' . $mime);
+    if ($download) {
+        header('Content-Disposition: attachment; filename="' . $basename . '"');
+    }
+    http_sendfile($pathInfo['path']);
+    readfile($pathInfo['path']);
+} catch (Exception $e) {
+    header('Content-Type: text/plain');
+    http_status(403);
+    echo $e->getMessage();
+    exit;
+}
+