Use encrypted ansible user and password when installing OpenShift

Issue

In some environments, the use of SSH keys is forbidden or simply not available. Also, variables containing sensible information like username (ansible_ssh_user) and password (ansible_ssh_password) for remote SSH connection are in plain text in inventory file, which may lead to a security breach if unauthorized people can access to OpenShift inventory file.

This article describes how to create a file (vault) which will contain all sensitive data in a encrypted format.