docs: removed mention of "hybrid" or "dedicated" clusters

[jackdelahunt]

Clusters used in RHOSAK are now referred to as just Openshift Clusters instead of the old dedicated or hybrid.

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Documentation change
• [ ] Other (please specify)

[jackdelahunt]

OpenShift Cluster here please

Done

[dimakis]

Lgtm 😁