feature: Added web validation (#7474)

* refactor: convert validations to modules to prep for gui integration

* accidentally dropped, schema update

* fix accidental output to webui

* mention discovery-wrapper.py and re-arrange.

* refine some fix statements

* rename the Config validation group to Configuration.

* fix some scrutinizer issues
remove as many local functions from validator.php as possible
move extensions from pre-check
remove duplicate timezone check
looks like there is some db schema differences between mariadb 10.1 and 10.2, investigating

* mariadb version diff take2

* Check schema version first for database.
Remove stop to go back to command line for install docs.
Add helpful link when there is no devices added to /addhost

* fix incorrect validation for empty string defaults

* Fix style

* Add additional file permissions checks

* catch exception and fail for invalid timezone
Change visuals a bit.

* add php version warning

* fix space

LibreNMS/Validations/Configuration.php

@@ -0,0 +1,57 @@
+<?php
+/**
+ * Configuration.php
+ *
+ * Checks various config settings are correct.
+ *
+ * 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 Tony Murray
+ * @author     Tony Murray <murraytony@gmail.com>
+ */
+
+namespace LibreNMS\Validations;
+
+use LibreNMS\Config;
+use LibreNMS\Interfaces\ValidationGroup;
+use LibreNMS\Validator;
+
+class Configuration implements ValidationGroup
+{
+    /**
+     * Validate this module.
+     * To return ValidationResults, call ok, warn, fail, or result methods on the $validator
+     *
+     * @param Validator $validator
+     */
+    public function validate(Validator $validator)
+    {
+        // Test transports
+        if (Config::get('alerts.email.enable') == true) {
+            $validator->warn('You have the old alerting system enabled - this is to be deprecated on the 1st of June 2015: https://groups.google.com/forum/#!topic/librenms-project/1llxos4m0p4');
+        }
+    }
+
+    /**
+     * Returns if this test should be run by default or not.
+     *
+     * @return bool
+     */
+    public function isDefault()
+    {
+        return true;
+    }
+}