Add utility to backfill log syncs from audit logs#268

RyandenOtter wants to merge 2 commits intoGoogleCloudPlatform:masterGoogleCloudPlatform/bigquery-utils:masterfrom

RyandenOtter:add_backfil_audit_logsRyandenOtter/bigquery-utils:add_backfil_audit_logsCopy head branch name to clipboard