Since we're still provisioning the Ceph cluster at step2 we need
to call the cephadm playbook the same way as ceph-ansible.
The purpose of this role is to be able to run the cephadm playbook
using external_deploy_steps_tasks.
The actions implemented in this role are:
1. prepare: build a cephadm dir within the config-download dump
2. enable_ceph_admin_user via cli-enable-ssh-admin.yaml playbook
3. translates the tht paramters and make them available to the role
4. call the ansible playbook that runs cephadm and apply the spec
Change-Id: If066dd19f1e9c75fd6581fddb5b55cb37eb57809