added Polish translations (#1426)

assets/js/plugins/KimaiDateUtils.js

@@ -0,0 +1,29 @@
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/*!
+ * [KIMAI] KimaiDateUtils: responsible for handling date specific tasks
+ */
+
+import KimaiPlugin from '../KimaiPlugin';
+import moment from 'moment';
+
+export default class KimaiDateUtils extends KimaiPlugin {
+
+    getId() {
+        return 'date';
+    }
+
+    getWeekDaysShort() {
+        return moment.localeData().weekdaysShort();
+    }
+
+    getMonthNames() {
+        return moment.localeData().months();
+    }
+
+}