Allow admin user to save query logs to Google Spreadsheet

[avacariu]

Sort of depends on issue #173 (although it doesn't have to)

The idea for this is when the query backend receives a query, it should append it to a Google Spreadsheet of all queries. This'll allow us to analyze the query data more easily.

The way this could work is either

• user will be walked through OAuth2 on command line by the query backend when it's being set up, or
• when the frontend is being set up, the OAuth2 request for the admin user could also include permissions for creating spreadsheets

I'm going to start with the former, but @anoopsarkar and I also discussed the latter as an option. Since the admin user will also sign in with Google+ Signin just like everyone else, the admin page could show the spreadsheet stuff as well.

[avacariu]

Oauth2 tokens can be invalidated randomly because there's a 25 token per Google account limit, and it's too tedious to renew tokens, and difficult to know when tokens will be invalidated.

Using syslog and parsing the logs afterwards is much simpler and more reliable.