Implement automin and automax for conditional formatting

User Story

Excel 2010+ supports conditional formatting using automin and automax boundaries. See details.

Keikai currently doesn't implement automin and automax, cause NPE on spreadsheet using automin or automax in conditional formatting.

See attached spreadsheet.

Acceptance Criteria

• Implement conditional formatting, or handle the automin automax conditional formatting values to avoid NPE
• If we can't implement this feature, please handle null pointer exception gracefully

Details

https://docs.microsoft.com/en-us/dotnet/api/documentformat.openxml.office2010.excel.conditionalformattingvalueobjecttypevalues?view=openxml-2.8.1

https://www.contextures.com/excel-conditional-formatting-data-bars.html