[autotest] Add a script to sync lab servers to CloudSql access control

For a lab server to access CloudSql database, the server's IP must be added to
the "Allowed Networks" list of the CloudSql database.

This tool is added to sync the servers in the list of "Allowed Networks".

BUG=chromium:507929
TEST=test run against a test CloudSQL instance
./site_utils/sync_cloudsql_access.py --project [name] --instance tko-test \
--extra_server 'server1,server2' --afe [prod autotest]

Change-Id: I9bf0ea1ccb7ee0e48ae7f55fc98368e2192917d5
Reviewed-on: https://chromium-review.googlesource.com/287620
Trybot-Ready: Dan Shi <dshi@chromium.org>
Tested-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Fang Deng <fdeng@chromium.org>
Reviewed-by: Mungyung Ryu <mkryu@google.com>
Commit-Queue: Dan Shi <dshi@chromium.org>
1 file changed