Add certificate options when placing digital signatures (#64)

[aphoe]

To add certificate options (reason, location, etc), you can now call set_metadata_props() before you call to_pdf_file_s()

Example:

   $cert = [
        'cert' => $certificate,
        'pkey' => $pkey,
    ];

    $obj = PDFDoc::from_string($pdf);

    $obj->set_signature_certificate($cert);
    $obj->set_metadata_props($name, $reason, $location, $contactInfo);

    $signed = $obj->to_pdf_file_s();

[aphoe]

Hi @dealfonso, can you create a v1.4.3 tag so we can pull it directly from Packagist with a composer update?

Thank you.

[dealfonso]

done

[aphoe]

Thank you very much