Update - Prerequistes and Concepts

[kumuduh]

https://cloud.redhat.com/experts/misc/jup/

test on 4.20 + and add an information banner saying "This guide has been validated on OpenShift 4.20. Operator CRD names, API versions, and console paths may differ on other versions." as this doc has https://cloud.redhat.com/experts/rosa/eso/

[nedoshi]

Archiving this content rather than updating, as it is outdated and has been superseded by Red Hat OpenShift AI (RHOAI). PR: #853