Add Quickbooks Online integration

- omniauth-quickbooks has an issue right now that a pull request has
  already been made to fix. Once it is fixed, the dependency can live
  here. Until then, it needs to be added manually to the main app.

- Uses a reduced data set for the reports, more can be added in the
  future.
Style/IndentationWidth: Use 2 (not -6) spaces for indentation.