Enumerate AlertState (#11665)

* Enumerate AlertState

* fix typo

* add missing use's

* .

* .

LibreNMS/Enum/AlertState.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * Alert.php
+ *
+ * Enumerates alarming Level
+ *
+ * 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  2020 Thomas Berberich
+ * @author     Thomas Berberich <sourcehhdoctor@gmail.com>
+ */
+
+namespace LibreNMS\Enum;
+
+abstract class AlertState
+{
+    const CLEAR = 0;
+    const ACTIVE = 1;
+    const ACKNOWLEDGED = 2;
+    const WORSE = 3;
+    const BETTER = 4;
+    const RECOVERED = 0;
+}