Add total line to .csv files exported from Discover

[#1]

Please add a total line to Discover reports exported in .csv format.  When the same report is download as an Excel file, the totals are present, so it's odd that the total line isn't included in the .csv file.

Keep in mind that oftentimes our reports are too large to download all rows of data, thereby making it impossible to calculate the sum using the downloaded file.