Implementation of a Heat stacks UI.

This change implements a UI to launch, manage and delete Heat stacks.

The launch screens are implemented with a set of chained forms where
the second form is dynamically built from the template in the first step.

A significant portion of this change was derived from
the work Dan Radez <dradez@redhat.com> did on thermal:
https://github.com/steveb/heat-horizon

UX flow revisions and basic test cases by Gabriel Hurley.

Implements blueprint: heat-ui

Change-Id: I294e93bed6da9dd3553e8b4a6a1c09b7c165a555
Temporary change the django_openstack_auth requirement

The new django_openstack_auth version causes gate job issues like:
http://logs.openstack.org/33618/5/gate/gate-tempest-devstack-vm-full/29950/console.html

Temporary disabling the 1.1.0 version.

Change-Id: Ide3546c9d254c1c6106745ab852a211d08a806de