Allow more file types

[steveoh]

for the MVP we stripped the accepted file types to CSV only. We should figure out what other file types people expect and implement them.

[steveoh]

from joe jackson

If you have a tool that can operate directly in Google Sheets I'd love to hear about it. That seems to come up frequently but the API Client will work if they're willing to export and import the data.

[stdavis]

Once upon a time, Keaton had a project that geocoded data in Google Sheets using Google App Scripts or some other native integration. I've always had it on my get-around-to-it list as something to check out. I think that it would be super-useful to build something that is native to gsuite.