Allow selecting last page for visual representation of signature placement
When applying bulk signatures, adding signature placement per-document could be a slow task. If all documents have the signature placement in the same position, but the page length differs, it is not possible to tell which page is the proper one, but it is possible to know which page from the last is the proper one for signing, so:
- Consider adding a check for indicating the page number for last
- Consider fallback to the last or fist page available when the value underflows or overflows
cc @luisza