phpstan support (#250)

* phpstan v1 + workflow

* Fix intend

* More fixes

* Update phpstan.neon

* phpstan level 2

* Move errors ignoring into phpstan.neon

* phpstan level 3

* Don't ignore templates folder

* Something from level 4

* Update phpstan.neon

phpstan-bootstrap.php

@@ -0,0 +1,13 @@
+<?php
+
+require __DIR__ . '/system/libs/pot/OTS.php';
+$ots = POT::getInstance();
+
+require __DIR__ . '/system/libs/pot/InvitesDriver.php';
+require __DIR__ . '/system/libs/rfc6238.php';
+require __DIR__ . '/common.php';
+
+const ACTION = '';
+const PAGE = '';
+const URI = '';
+define('SELF_NAME', basename(__FILE__));