Dashboard widget update (#9515)

Implemented in Laravel
Doesn't use legacy PHP session
Several widgets have new features and settings, for example:

- Multiple ports in one graph
- Maps settings are configurable and override system settings but default to system settings
- Graylog stream and/or device selection
- Much improved graph widget selection
- Many more

DO NOT DELETE THIS TEXT

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app/Http/Controllers/Widgets/NotesController.php

@@ -0,0 +1,63 @@
+<?php
+/**
+ * NotesController.php
+ *
+ * -Description-
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ * @package    LibreNMS
+ * @link       http://librenms.org
+ * @copyright  2018 Tony Murray
+ * @author     Tony Murray <murraytony@gmail.com>
+ */
+
+namespace App\Http\Controllers\Widgets;
+
+use Illuminate\Http\Request;
+use Illuminate\View\View;
+use LibreNMS\Util\Html;
+
+class NotesController extends WidgetController
+{
+    protected $title = 'Notes';
+    protected $defaults = [
+        'title' => null,
+        'notes' => null,
+    ];
+
+    public function getView(Request $request)
+    {
+        $settings = $this->getSettings();
+
+        if (is_null($settings['notes'])) {
+            return $this->getSettingsView($request);
+        }
+
+        $purifier_config = [
+            'HTML.Allowed'    => 'b,iframe[frameborder|src|width|height],i,ul,ol,li,h1,h2,h3,h4,br,p,pre',
+            'HTML.Trusted'    => true,
+            'HTML.SafeIframe' => true,
+            'URI.SafeIframeRegexp' => '%^(https?:)?//%',
+        ];
+        $output = Html::display(nl2br($settings['notes']), $purifier_config);
+
+        return $output;
+    }
+
+    public function getSettingsView(Request $request)
+    {
+        return view('widgets.settings.notes', $this->getSettings());
+    }
+}