Allow to show the footprint image in part info.

Also added an placehoder image for parts, who dont have an image.

src/Services/AttachmentFilenameService.php

@@ -0,0 +1,59 @@
+<?php
+/**
+ *
+ * part-db version 0.1
+ * Copyright (C) 2005 Christoph Lechner
+ * http://www.cl-projects.de/
+ *
+ * part-db version 0.2+
+ * Copyright (C) 2009 K. Jacobs and others (see authors.php)
+ * http://code.google.com/p/part-db/
+ *
+ * Part-DB Version 0.4+
+ * Copyright (C) 2016 - 2019 Jan Böhmer
+ * https://github.com/jbtronics
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ *
+ */
+
+namespace App\Services;
+
+
+use Symfony\Component\Asset\Packages;
+
+class AttachmentFilenameService
+{
+    protected  $package;
+
+    public function __construct(Packages $package)
+    {
+        $this->package = $package;
+    }
+
+    public function attachmentPathToAbsolutePath(?string $filename) : ?string
+    {
+        //Return placeholder if a part does not have an attachment
+        if ($filename == null) {
+            return $this->package->getUrl('/img/part_placeholder.svg');
+        }
+        if (stripos($filename, "%BASE%/img/") !== false) {
+            return $this->package->getUrl(str_replace('%BASE%', '', $filename));
+        }
+
+        //If no other method works, return placeholder
+        return $this->package->getUrl('/img/part_placeholder.svg');
+    }
+}