Set filename for export explicitly

(I look to you Chrome!) See issue #1

packages/data-table-view/src/vpu-data-table-view.js

@@ -102,11 +102,13 @@ class DataTableView extends LitElement {
                     extend: 'csvHtml5',
                     text: 'CSV',
                     title: this.exportName,
+                    filename: this.exportName,
                 },
                 {
                     extend: 'excelHtml5',
                     text: 'XSLX',
                     title: this.exportName,
+                    filename: this.exportName,
                 },
                 {
                     extend: 'print',