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.

Previously forgot to add deepclean and gwhen robot users to the
LVC group.

Move a number of scripts which were managed in a separate repo
into management commands.  This way they can be more easily executed
either manually or by cron jobs.

Fixing two migrations
  - ligoauth 0004: properly delete User instance for gstlal-spiir-gpu,
    not just LocalUser/RobotUser
  - ligoauth 0013: deleted, since gstlal-spiir-gpu has been deleted,
    we don't need to create a RobotUser instance for it

We had removed the ability for GraceDbModelBackend to do
authentication, but it is relied on for basic auth by the
BasicAuthentication class in django-rest-framework.  So we undo
that change and remove the GraceDbModelBackend class altogether
in favor of its parent, ModelPermissionsForObjectBackend.

ControlRoomMiddleware is a new-style middleware, but that makes it
somewhat hard to unit test.  So we just split up the request and
response processing into separate functions which are called
within the __call__ function.

For the base test class which creates an LV-EM user and the
LV-EM observers group, we now also create the basic LV-EM group
and add the user to it as well.

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.