Added pt_BR to language dropdown and renamed folder

-<?php
-
-namespace BookStack\Http\Middleware;
+<?php namespace BookStack\Http\Middleware;
 
 use Carbon\Carbon;
 use Closure;

@@ -117,6 +117,7 @@ return [
         'en' => 'English',
         'de' => 'Deutsch',
         'fr' => 'Français',
+        'pt_BR' => 'Português do Brasil'
     ]
     ///////////////////////////////////
 ];