Add a section to the RHPAM/RHDM on Openshift explaining that the client side of SSO should be created first

As part of the RHPAM-1307, we implemented a feature that try to guess the default hostnames for the BC and Kieserver based on the pod names if the user do not set the vars:

• BUSINESS_CENTRAL_HOSTNAME_HTTP
• BUSINESS_CENTRAL_HOSTNAME_HTTPS
• EXECUTION_SERVER_HOSTNAME_HTTP
• EXECUTION_SERVER_HOSTNAME_HTTPS

This should be documented on our templates recommending the customer to set those vars to have more control of the RH-SSO integration, otherwise the containers will use the auto-generated routes.

Also, as a note of good practice will be advising the customer to create the SSO Client before hand and then set the variables accordingly:

• SSO_URL
• SSO_REALM
• *_SSO_SECRET
• *_SSO_CLIENT

This way the container will NOT create this client automatically, giving the customer much more control of this configuration.

We could use this doc [1] as a reference.

[1] - https://access.redhat.com/documentation/en-us/red_hat_process_automation_manager/7.3/html/integrating_red_hat_process_automation_manager_with_red_hat_single_sign-on/index