Create `DEV` environment for Google Sheets

[lucasmbrown]

Right now, when we're testing new functionality and want to confirm the data is posted to Google Sheets and that it appears to be accurate, it's a little dangerous to test because we override all of the data in the Google Sheets used for production every time we run the main extract_transform_and_load_covid_data method.

(We do have some buffer from PROD because Ryan copies and pastes this data into other sheets that back DataWrapper and the website.)

Could we create a folder of Google Sheets that are used as a DEV or STAGING environment for testing things before they're merged to master?

For instance, a simple approach to this might be to create a dictionary of environment names mapped to a dictionary of sheet names mapped to sheet identifiers. That way when you're running in DEV/STAGING, you'll post all the data to a different set of sheet identifiers.