Data validation: support minimum or maximum date or integer values

[cfsimplicity]

Data validation currently supports ranges of acceptable dates or integers by setting the min and max values:

spreadsheet.newDataValidation()
  .onCells( "A1:B1" )
  .withMinInteger( 1 )
  .withMaxInteger( 100 )

Allow setting just a min or max value for each data type, ie supporting "greater than or equal" and "less than or equal" comparisons:

spreadsheet.newDataValidation()
  .onCells( "A1:B1" )
  .withMinInteger( 10 )

spreadsheet.newDataValidation()
  .onCells( "A1:B1" )
  .withMaxDate( CreateDate( 2020, 12, 31 ) )

(Thanks to Tim Carley for input)