Some logging events

* When pay.gov makes a callback, log the success or failure
* Make sure to delete donor info when above callback is a failure
* When clearing stale donor information, log how many were removed
* When synchronizing account information, log when a new account is added, updated, or a failure occurred (due to invalid country/sector)
* Remove the reliance on the 'tests.yaml' fixture from the synchronization tests. Locally that sped test execution from 35s to 22s
It seems like something went wrong in this case, would we want to log.error or log.warn?