[Format] Accept CSV on https://redu.ucsd.edu/ReDUValidator

[Adafede]

Hi,

As the template is provided as an .xlsx spreadsheet and Excel many users will probably use Excel to fill it, it might need an additional step to convert it to TSV. Excel mainly favors CSV (afik), so could be nice to reduce user's workload.

[mwang87]

I think thats a great idea. One thing I'm wanting to do in my new lab is a big revamp and streamlining of metadata representation. This could be along these lines and will make ReDU like way way better in the long run. Lets work together on this!

Best,

Ming