Provide info for the following steps:

1. - [x] Mandatory Add the required version to the Fix version/s field.

2. - [x] Mandatory Choose the type of documentation change.

      - [ ] New topic in an existing section or new section
      - [x] Update to an existing topic

3. - [x] Mandatory for GA content:
            
       - [x] Add steps and/or other important conceptual information here: 

Document prerequisites for deploying bare metal clusters with BMC.

Which ports to open for bare metal clusters?

Some info here: https://docs.openshift.com/container-platform/4.13/installing/installing_aws/installing-aws-expanding-a-cluster-with-on-premise-bare-metal-nodes.html

"I cannot find what ports to have open for a BareMetal managed cluster install, I know I need 443/6443 in general but cannot find in our documentation what else is needed, pretty much the whole deploy a BareMetal cluster seems to be lacking some information or I just cannot seem to find it"

"We have 6138 / 5050 and a couple of other ports open, and what we see is that the bootstrapped BM server is trying to connect back to the hub (ACM) on 5050, but there are no node ports or routes for that to happen, here is the link to the case https://access.redhat.com/support/cases/#/case/03588408"
            
       - [x] Add Required access level for the user to complete the task here:

cluster admin
       

       - [x] Add verification at the end of the task, how does the user verify success (a command to run or a result to see?)

The user must configure their network to open the ports, there is no easy way to verify other than trying to proceed.
     
       - [ ] Add link to dev story here:

4. - [x] Mandatory for bugs: What is the diff? Clearly define what the problem is, what the change is, and link to the current documentation:

This needs to be added to CIM prerequisites where the baremetal operator is discussed.