Added dataTables.buttons plugin

Author: DavidSuescunPelegay

src/jQueryDatatableServerSideNetCore/Views/TestRegisters/Index.cshtml

@@ -57,5 +57,7 @@
     <script src="~/lib/datetime-moment/datetime-moment.js" asp-append-version="true"></script>
     <script src="~/lib/datatables/js/dataTables.bootstrap4.js" asp-append-version="true"></script>
 
+    <script src="~/lib/datatables-buttons/dataTables.buttons.min.js" asp-append-version="true"></script>
+
     <script src="~/js/app.js" asp-append-version="true"></script>
 }