Create an informative issue (See each section, incomplete templates/issues won't be triaged)

Using the current documentation as a model, please complete the issue template. 

Note: Doc team updates the current version and the two previous versions (n-2). For earlier versions, we will address only high-priority, customer-reported issues for releases in support.

Until now, there were two options in the UI to add hosts to an infra env:

• using BMC
• downloading the discovery is

after this change, a third one will be added, the iPXE

Prerequisite: Start with what we have

This section describes which how hosts can be added today:

https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.7/html-single/clusters/index#scale-hosts-infrastructure-env

It needs to be enriched by a new option, "with iPXE".

Describe the changes in the doc and link to your dev story

Provide info for the following steps:

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

2.8

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

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

The topic already describes "download iso" and "bmc" options, the new option "iPXE" needs to be added.

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

The screenshots are in this patch: https://github.com/openshift-assisted/assisted-ui-lib/pull/1987 (start from bottom and goes up)

A new section needs to be added between 5 (using iso) and 6 (using bmc) in https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.7/html-single/clusters/index#scale-hosts-infrastructure-env.

This section should look like this:

If you select the With iPXE option, complete the following steps:

1: (optional) fill in the optional fields in the form

2: click "generate script file" button

3: click "download script file" and follow the instructions in the dialog to boot the hosts using iPXE

            
       - [ X ] Add Required access level for the user to complete the task here:

no changes compared to the other options

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

Hosts successfully show up in the infra env
     
       - [ X ] Add link to dev story here:

https://issues.redhat.com/browse/MGMT-9939

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