Stevenson Michel

@gulien should we try encrypting a file first if metadata is requested and then add metadata after? I see that [exifTool](https://github.com/alchemy-fr/exiftool/blob/master/lib/Image/ExifTool/PDF.pm) can read/write metadata to encrypted documents provided the password...

ok, I have a solution that I think works fine @gulien ```go // EncryptPdfStub adds password protection to PDF files. func EncryptPdfStub(ctx *api.Context, engine gotenberg.PdfEngine, userPassword, ownerPassword string, inputPaths []string)...