currently the signers use the python logging module to write everything to a single file, and when it goes to rotate the file, it also archives the file to GS for long term storage.  this isn't the best way for integrating with our tools, or for developers to find.

GCS has stackdriver logging [1] which offers a number of features and better UI/search.  it offers a python module [2] too.

we should be able to experiment by bolting it into our existing python logging usage -- we can add another handler to SetupLogging after we've added the other handlers which would just send the line to stackdriver.

stackdriver also has integration with alerts.  so we might be able to use that instead of our ad-hoc e-mail generation.

[1] https://cloud.google.com/logging/
[2] https://cloud.google.com/logging/docs/setup/python