Add error handling for writing out to Google Sheets

[gilliganondata]

There seems to sometimes be issues with Google Sheets.

In those cases, ideally, there would be a graceful fail whereby the HTML file would still get generated and the underlying data would all get written out to an .rda file (or something) so that a separate script could read in that file and just write it out to Google Sheets.

There is the ability to switch a flag (use_local_files: change from FALSE to TRUE) to populate the Google Sheet using locally stored data rather than re-querying. This is a partial fix--just speeds up subsequent runs if the only issue was that the hang-up happened on writing to Google Sheets.