refactor: Refactor alert transports to classes (#7844)

* Refactor alert transports to classes

* Fix linting

* Make Slack alert transport php 5.3 compatible

* Rename call method to deliverAlert for alert transport

LibreNMS/Interfaces/Alert/Transport.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * Transport.php
+ *
+ * An interface for the transport of alerts.
+ *
+ * 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  2017 Robrecht Plaisier
+ * @author     Robbrecht Plaisier <librenms@mcq8.be>
+ */
+
+namespace LibreNMS\Interfaces\Alert;
+
+interface Transport
+{
+    /**
+     * Gets called when an alert is sent
+     *
+     * @param $alert_data array An array created by DescribeAlert
+     * @param $opts array|true The options from $config['alert']['transports'][$transport]
+     * @return bool Returns if the call was successful
+     */
+    public function deliverAlert($alert_data, $opts);
+}