Add support for Spanish [skip ci]

resources/lang/es_ES/config.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * config.php
+ * Copyright (c) 2017 thegrumpydictator@gmail.com
+ *
+ * This file is part of Firefly III.
+ *
+ * Firefly III 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.
+ *
+ * Firefly III 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 Firefly III. If not, see <http://www.gnu.org/licenses/>.
+ */
+declare(strict_types=1);
+
+return [
+    'html_language' => 'es',
+    'locale'        => 'es, Spanish, es_ES, es_ES.utf8, es_ES.UTF-8',
+    'month'         => '%B %Y',
+    'month_and_day' => '%B %e, %Y',
+    'date_time'     => '%B %e, %Y, @ %T',
+    'specific_day'  => '%e %B %Y',
+    'week_in_year'  => 'Semana %W, %Y',
+    'year'          => '%Y',
+    'half_year'     => '%B %Y',
+];