These settings were previously handled in settings/container/production.py,
but we want to do some testing and I don't see any issues with having
them in the base container settings (settings/container/base.py).

These environment variables are now required.  Previously, the
corresponding Django settings would default to 'gracedb'.

This will (hopefully) allow us to receive error emails from the
container deployments on AWS.

Add a logging handler for printing to stdout. For container
deployments, we remove all other logging handlers and use this
new 'console' handler only. The incantation for starting
gunicorn with supervisord now sends the access and error logs
to stdout.

Containerized versions of the service will now get their LVAlert
credentials from the environment.  Also add a script for
processing environment variables and starting LVAlert overseer.

New API backend which gets a full X509 certificate, verifies it,
and extracts the subject.  To be used in the cloud deployment
with Traefik.

Settings have been reorganized and how different parameters are
determined has been reworked to be compatible with both a Puppet-based
VM deployment and a containerized deployment