Add XLSX option helpers to SimpleExcelReader

[brodos]

This PR adds the XLSXOptions to SimpleExcelReader, which then allows using some new helpers to set some options for XLSX files.

Preserve date formatting

By default, when reading a spreadsheet with dates or times, the values are returned as DateTimeImmutable objects. To return a formatted date (e.g., “9/20/2024”) instead, use the preserveDateTimeFormatting method. The date format will match what’s specified in the spreadsheet.

$rows = SimpleExcelReader::create($pathToXlsx)
    ->preserveDateTimeFormatting()
    ->getRows();

Preserve empty rows

You can preserve empty rows by using the preserveEmptyRows method.

$rows = SimpleExcelReader::create($pathToXlsx)
    ->preserveEmptyRows()
    ->getRows();

[Nielsvanpach]

Nice PR, thanks!