Move files in typical src and tests folder (#242)

* Move files in typical src and tests folder

* Fix psalm error

src/Warning/IPV6MaxGroups.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Egulias\EmailValidator\Warning;
+
+class IPV6MaxGroups extends Warning
+{
+    const CODE = 75;
+
+    public function __construct()
+    {
+        $this->message = 'Reached the maximum number of IPV6 groups allowed';
+        $this->rfcNumber = 5321;
+    }
+}