Rewrite data model to be pure hiera

This (enormous) patch adds experimental support
for a distribution that uses pure hiera in place
of the scenario_node_terminus.

A python script can be used to convert from the SNT
data model to the pure hiera one:
contrib/aptira/build/convert.py
It requires PyYaml, and will back up the old data
directory to data.old. It is not even remotely idempotent.

Data mappings are expressed using interpolation except
in the case where they are non-string, in which case
yaml anchors are used. At this time, YAML anchors are not
working across files, which places some restrictions on
their use.

Scenarios are now a part of the hiera_data folder,
and each scenario yaml file contains its mappings,
globals, and in future probably its 'user.scenario.yaml'
data.

Roles are under scenarios/%scenario/$role, and use a hiera
lookup of 'classes' and 'class_groups' to include classes.

Class groups are a new yaml file in hiera_data, and have
been changed to be string quoted since starting yaml keys
with a % is invalid.

Globals are not handled correctly at this point. They need to be
converted into a new structure based around hiera_data/contrib, which
will allow arbitrary class includes, but is not quite finished.

A new install script has been added at
contrib/aptira/install/bootstrap.sh that is an idempotent bash script.
This script will install ruby 2.0.0 from a prebuild rpm and then
install puppet from gem. It then configures hiera and uses the data
model to set up pre-puppet config without needing to run puppet.

A new Vagrantfile has been added under contrib/aptira/build that is
Vagrant 1.5 compatible, which uses the new bootstrap script.

In addition, a new scenario called stacktira has been added, which
uses a new galera module and a new module for openstack general
functionality called openstacklib. This scenario is added using
the node_terminus style of yaml, but functions when converted using
the aforementioned convert.py

Change-Id: Iaa00b165e2933cdb8c5149343b3cfe40bcc8b3db