Update base.py: updating the version number to "2.7.1-1". There's no functional differences, just a few settings for the new AWS deployment. I'm also adding the "*-1" qualifier so that I and users can tell that the new AWS deployment is in place and working. 

This is not needed anymore with the changes to the group infrastructure
which add an optional 'ldap_name' to groups whose membership should be
managed by LDAP queries and shib sessions.

ligoauth.models.AuthGroup is an enhanced version of the builtin Django
Group model. We add useful attributes like a description, ldap_name,
and Tag.  These can be used to abstract things that are presently
handled manually, like inheriting membership from an LDAP group or
allowing access to view log messages/files with a specific Tag.

I ran some tests comparing this multi-table inheritance setup to
adding a OneToOneField and loading it with/without select_related.
After 1K trials, the DB query times looked comparable and didn't
require multiple queries for this arrangement, so the convenience
seems to be worth it.

The commit creates the model and populates an instance for existing
each existing Django Group.

When applied, this makes a view publicly available *if* the
settings.UNAUTHENTICATED_ACCESS switch is True; otherwise you
must be authenticated. This will be useful to propagate to
most other views to make this settings switch globally effective
at some point.

Instead of looping over EmailMessage.send() calls, we now get the
email backend and send a list of messages. Note that the backend
sends the messages individually still but this cuts out some of the
overhead.

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.

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.

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.

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.