Add guidgrabber / RHPDS usage notes

[ryanj]

Add usage notes for deploying a large workshop environment (for multiple users) using guidgrabber and RHPDS

The agnosticd script is currently configured to deploy the v1.1 release:

• https://github.com/openshift-labs/lab-build-your-own-operator/releases
• https://github.com/redhat-cop/agnosticd/blob/development/ansible/roles/ocp4-workload-build-your-own-operator/tasks/workload.yml#L20

A new release ( v1.2? ) will need to be cut to make the latest available via RHPDS and other lab tooling