We use a few redirects to handle login and extraction of the
shibboleth attributes in a post-login page.

Can be used to restrict access to a view to only the groups
whose names are passed as arguments to the decorator.

Complete rework of authentication middleware and backends for
both the web view and the API. There is now a single URL (after
the login page) where the shibboleth attributes are put into
the session and the user is authenticated and a persistent
Django session is created.

No need to have explicit view functions for a few basic views,
we just use the built-in TemplateView instead.

Add access_managers and superevent_managers to ADMIN_MANAGED_GROUPS.
They will be removed in the near future, but for now, they should
be included here so that group memberships are not removed by the
ligoauth middleware.

silk was slowing things quite a bit so we won't use it by default,
even in development instances.

Rename config/settings/test.py -> config/settings/dev.py to prevent
the file from being picked up by the test runner during unit testing.

Now require version 2.0.0 of the client and won't allow old
versions without the client header.

Instantiating a second version for the API.  For now, it's identical
to v1, but can be customized as needed in the future.

Moving a few base class throttles and fields from the events app up
one level so that they can be used elsewhere.

Moved events.api and superevents.api into the new api app.
We want to have a versioned API, so these are now in
api.v1.events and api.v1.superevents, respectively. Part of this
change is that we require a custom reverse function (api_reverse)
for handling versioning. Much of the required code changes for this
migration include converting reverses to use this function and
changing relative imports appropriately.

Added utility functions for hiding and exposing logs from
LV-EM and the public. They are triggered by log messages being
tagged or untagged.

Also added utilities for hiding/exposing superevents.

New custom model backend, which includes the table/object
permissions backend and does not authenticate.

New /latest/ page includes events and superevents. We also
move the old events 'latest' page to /events/latest/, changed the
view name, and fixed reverses to that page appropriately.

Modified events.view_utils.reverse to return an absolute url using
core.urls.build_absolute_uri.  This is helpful for when we issue
alerts without a request object available to construct the absolute
url.  Also updated the corresponding *toDict methods so as to
take advantage of this.

Activate Django sites app and create a migration which adds the
LIGO.ORG domain name of the GraceDB instance as a Site. This will
be used to build absolute URIs without needed a request object.

Instantiating a new alerts app and moving the alert functionality from
events/alert.py to alerts/old_alert.py. This commit forms a starting
point where the old alert functionality is still in place and we can
rework the alert infrastructure to be more modularized, flexible,
and adapted to superevents.

Renaming LIB -> oLIB and gstlal-spiir -> spiir, at the request of
the pipelines.

Updated from Django 1.11.5 to Django 1.11.14. Updated 3rd party
packages so that all of them have version requirements in
requirements.txt.  Also updated most of these packages to use the
newest versions.  A specific update to the twilio package required
some changes for how we determine the 'from' phone number. Also
alphabetized the packages in this file.  Finally, added the very
useful django-silk debugger/profiler.

django-extensions was just in the test settings before (i.e., not
deployed on production), but it is pretty nice and useful, so we
are moving it into the base settings so that it can be used
everywhere!

Adding middleware which checks the client version (for everything
under /api*) by using the User-Agent header. Obviously requires the
client to set the header appropriately as well.  Allows access
when the header is set but 'gracedb-client' is not found in it
since browsers have to access the web browsable API.

Unsure why messaging app was not enabled; it's needed for
posting flash messages about contacts and notifications.