Create keystone roles and admin user from t-h-t manifests

Create keystone roles and admin user from t-h-t manifests

Currently keystone initialization happens via os-cloud-config [1].

This commit moves some of that directly into the manifests. This is the
first in a series of two changes to migrate it entirely into t-h-t.

This change focus on implementing what keystone.initialize() was doing
on the tripleoclient [2], creates the admin tenant, user and roles.

It also creates the keystone endpoint itself.

1.  https://github.com/openstack/os-cloud-config/blob/master/os_cloud_config/keystone.py#L128-L158
2.  https://github.com/openstack/python-tripleoclient/blob/master/tripleoclient/v1/overcloud_deploy.py#L462-L527

Change-Id: I98555b707ff9b91c6e218de5dca68106ea05c8ea
Depends-On: Ia4b3244f114dcff746ab89d355ad4933f8fdbddf