[WIP] Implement repeat requests on GSuite

[skiptomyliu]

• We make a lot of requests to GSuite. This makes it more resilient in case of a Google server blip, which we've seen.
• Refactor the transform objects method to be more general to prevent copy-pasta.

[achantavy]

@skiptomyliu @tayasteere Can you please provide more information on the failures? Which data is missing and on which function calls? Do we have stack traces available for these failures? Can we repro?

Would like to more thoroughly understand and document the failure before adding retries.

[skiptomyliu]

We receive 5xx Service Unavailable from Google's API call. Scrubbed stack trace:

{"ts": "2019-09-12T21:35:26.334Z", "uuid": "2fdb2fbf-d6d7-4d47-8472-76e12f0ede90", "app": "infraintelgraph", "name": "cartography.intel.gsuite.api", "lvlname": "WARNING", "lvlno": 30, "pid": 31966, "call_site": "srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/cartography/intel/gsuite/api.py:266", "revision": "e6105806c2", "msg": "HttpError occurred in api.get_all_groups(), returning empty list. Details: <HttpError 503 when requesting https://www.googleapis.com/admin/directory/v1/groups?customer=my_customer&maxResults=20&orderBy=email&alt=json&pageToken=..."}
{"ts": "2019-09-12T21:35:26.337Z", "uuid": "6f25e5d0-30fc-4d36-bb89-11ed6578ec44", "app": "infraintelgraph", "name": "cartography.intel.gsuite.api", "lvlname": "INFO", "lvlno": 20, "pid": 31966, "call_site": "srv/venvs/service/trusty/service_venv_python3.6/lib/python3.6/site-packages/cartography/intel/gsuite/api.py:268", "revision": "e6105806c2", "msg": "Ingesting 0 gsuite groups"}

As soon as that occurs, we break out of the loop and return an empty list. The cleanup script is then run which removes the old entries. I think to make this more resilient we can:

1. Add retries (what this PR does) because we make a lot of API calls due to the pagination (i'd estimate perhaps multiple hundreds of calls largely due to fetching group membership)
2. Don't run the cleanup script if empty lists are returned

[skiptomyliu]

Redoing PR with: #169

CLA signing is borked when I re-configured my new laptop and didn't setup my github config yet.