Change "Deploying workloads on ... " to "Deploying on ...".

Reason for change: These sections describe how to deploy sandboxed containers, not just workloads, on different platforms.

We have no approved abbreviation for OpenShift sandboxed containers. I do not recommend "Deploying OpenShift sandboxed containers on <platform>" because it makes the headers quite long and it is unnecessary in a user guide for a single project.