Update RHDH Quick starts to incl. some CRD specific information [4.16]

Description of problem:
The OpenShift Console QuickStarts that promotes RHDH was written in generic terms and doesn't include some information on how to use the CRD-based installation.

We have removed this specific information because the operator wasn't ready at that time. As soon as the RHDH operator is available in the OperatorHub we should update the QuickStarts with some more detailed information.

With a simple CR example and some info on how to customize the base URL or colors.

Version-Release number of selected component (if applicable):
4.15

How reproducible:
Always

Steps to Reproduce:
Just navigate to Quick starts and select the "Install Red Hat Developer Hub (RHDH) with an Operator" quick starts

Actual results:
The RHDH Operator Quick start exists but is written in a generic way.

Expected results:
The RHDH Operator Quick start should contain some more specific information.

Additional info:
Initial PR: https://github.com/openshift/console-operator/pull/806