♻️(frontend) doc title as title for pdf export

Our pdf export was named impress-document.pdf,
now it is named after the document title.
We sanitize the title by removing special characters,
replacing spaces with underscores and putting it
in lowercase.

src/frontend/apps/impress/src/features/pads/pad-tools/components/ModalPDF.tsx

@@ -57,7 +57,14 @@ export const ModalPDF = ({ onClose, templateOptions, pad }: ModalPDFProps) => {
       return;
     }
 
-    downloadFile(pdf, 'impress-document.pdf');
+    // normalize title
+    const title = pad.title
+      .toLowerCase()
+      .normalize('NFD')
+      .replace(/[\u0300-\u036f]/g, '')
+      .replace(/\s/g, '-');
+
+    downloadFile(pdf, `${title}.pdf`);
 
     toast(t('Your pdf was downloaded succesfully'), VariantType.SUCCESS);