Refactor manifest execution

Previously, Packstack created many individual manifest files from
smaller snippets (templates), and executed them following a certain
order. This is sub-optimal, since it forces code duplication and goes
against the Puppet design of running a single manifest.

This patch refactors the manifest execution, following these principles:

- Only 3 templates used, so max 3 Puppet executions on a host: controller
  manifest, network node manifest, compute node manifest.

- The previous snippets are now part of the Packstack Puppet module, and
  included as needed by the controller/network/compute manifests. This
  concept is similar to the one used by the puppet-openstack-integration
  project [1].

- The remaining Python code is left untouched, so we can keep complete
  compatibility with previous answer files.

- Redis HA support has been removed, as this was the only service with
  HA enabled and didn't fit the general purpose of Packstack.

[1] - https://github.com/openstack/puppet-openstack-integration

Change-Id: I87591be0fce98079c85c5c12ad76ea7115fb9c75

packstack/puppet/modules/packstack/manifests/ironic.pp

@@ -0,0 +1,17 @@
+class packstack::ironic ()
+{
+    create_resources(packstack::firewall, hiera('FIREWALL_IRONIC_API_RULES', {}))
+
+    ironic_config {
+      'glance/glance_host': value => hiera('CONFIG_STORAGE_HOST_URL');
+    }
+
+    class { '::ironic::api':
+      auth_uri       => hiera('CONFIG_KEYSTONE_PUBLIC_URL'),
+      admin_password => hiera('CONFIG_IRONIC_KS_PW'),
+    }
+
+    class { '::ironic::client': }
+
+    class { '::ironic::conductor': }
+}