title: Prevent writeDataTable (openxlsx) from writing any column names
body: <p>When writing a table to an Excel workbook:</p>
  
  <pre><code>wb &lt;- createWorkbook()
  addWorksheet(wb, "Data")
  data &lt;- tibble(x = seq(1,10), y = c("A","B","C","D", NA, NA, NA, NA, NA, NA))
  writeDataTable(wb, sheet = "Data", x = data, colNames = FALSE, withFilter = FALSE, tableStyle = "none")
  saveWorkbook(wb, file = "Temp.xlsx", overwrite = TRUE)
  </code></pre>
  
  <p>Even when <code>colNames = FALSE</code>, names are written - it's just that the actual column names are replaced by "Column1", "Column2" etc.</p>
  
  <p>Is there a way to get writeDataTable to write the table and completely omit the column names - so that the first data value in the data.frame is written at A1 (or wherever specified), not "Column1"?</p>