Not feasible to use multiple DBs for read or write operations at
present. We're going to have to revisit this at some point. We leave
most of the code in place but commented out.

Small fixes to the main "index" view for alerts. Move the
manage_password page for LV-EM observers to the ligoauth app and
show a link to it from the navbar to those users.

Separate phone and email contacts, add verification of contact
information, improve views and forms.

Since the web view makes a few API requests to load log messages and
other content, we have to allow more requests. Also, it sounds like
users at a university might all appear to be on the same IP address,
so we want to try to account for that.

Not working as expected, so we are going to have to revisit this
feature in the near future.

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.

Traefik can pass the subject and issuer in a 'cert-infos'
header, so I am adding an authentication backend to use that.

Non-priority production containers will use the master for
writes and a read-replica database for reads. This commit adds
functionality for getting the replica's information from
environment variables and sets up a database routing scheme.

The settings for gracedb-playground are no longer on a separate
branch and are just included in master. They can be selected
simply by settings the DJANGO_SETTINGS_MODULE environment variable
appropriately.  This should be much easier to maintain than a
completely separate branch.

All throttles now use a database-backed cache since that is the
only way to do centralized throttling (important for production
deployment with multiple workers). We also add default throttles
for anonymous users for the entire API.

Various javascript functionalities and forms in the web interface
make calls to the API to get or process data. The current
Apache configuration (verify a certificate IF presented on /api/*)
causes pop-ups for users who have certificates in their browsers
if they visit any pages which have these functionalities. So we have
changed all of those URLs to use /apiweb/ for now to prevent the
certificate challenge.  This will be resolved in the future by
getting away from certificate-based authentication.

VOEvent IVORNs now use ivo://gwnet/LVC instead of
ivo://gwnet/gcn_sender. Also use the default superevent ID everywhere
in a VOEvent, including filename, even if it has a GW ID.

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.