Task scope: Fix this title and cherrypick to all supported versions (4.12+)

Documentation URL: https://docs.openshift.com/container-platform/4.16/installing/installing_bare_metal_ipi/ipi-install-installation-workflow.html#deploying-the-cluster-via-the-openshift-installer_ipi-install-installation-workflow

Problem: the title shows Setting up the environment for an OpenShift installation, while that should be the title of a sub-section. It looks as if it had some main title that was lost and this title of the subsection became the main title, which is wrong.

It is very problematic because if a user is looking how to install a baremetal IPI cluster, they go to "Installing-->Setting up the environment for an OpenShift installation" and they see the following list:

• Overview
• Prerequisites
• Setting up the environment for an OpenShift installation
• Postinstallation configuration
• ...

And the immediate question is: "I have the requirements and the post-installation but, where is the installation?" It is not trivial to know that the installation steps are in a section whose name is Setting up the environment for an OpenShift installation, as it looks like you only setup the environment for the installation.