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

Parent epic https://issues.redhat.com/browse/ACM-8285

Task parent: https://issues.redhat.com/browse/ACM-8285

Subtask https://issues.redhat.com/browse/ACM-11015

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.

Prerequisite: Start with what we have

Always look at the current documentation to describe the change that is needed. Use the source or portal link for Step 4:

 - Use the Customer Portal: https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes

 - Use the GitHub link to find the staged docs in the repository: https://github.com/stolostron/rhacm-docs 

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

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

3. - [ ] Mandatory for GA content:
            
       - [ ] Add steps and/or other important conceptual information here: 
       
            
       - [ ] Add Required access level for the user to complete the task here:
       

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

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

Changes: 

change #1

Add a new section after this 

https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.10/html/business_continuity/business-cont-overview#enabling-the-backup-operator

New section named

1.1.3.1.3. Installing the  OADP operator

Content for the new section:

For hub clusters where the STS (AWS Security Token Service) option is enabled, the OADP operator is not installed when the cluster backup and restore operator is installed on the hub cluster. The user must install this operator manually since he needs to pass the STS role_arn to the OADP operator at the time the operator is installed. Follow the OADP install procedure for configuring and installing OADP with an STS token. ( link this https://docs.openshift.com/rosa/rosa_backing_up_and_restoring_applications/backing-up-applications.html )

Note that as soon as you enable the backup option on the MultiClusterHub, this resource will remain in Pending state until the OADP operator is installed in the open-cluster-management-backup namespace, automatically by the chart or, in the STS case, installed manually, by the user.

For hub clusters where the STS option is not enabled, the OADP operator is installed automatically when the cluster backup and restore operator is installed on the hub cluster. 

change #2

Update https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.10/html/business_continuity/business-cont-overview#dr4hub-install-backup-and-restore

a. Move the Note: and Important sections under the  

1.1.3.1.3. Installing the  OADP operator 

b. Remove this from Notes ( is ambiguous , confusing) 

• Before you can use the backup and restore operator, you must set up hub clusters.

c. Remove this from Important : If you have previously installed and used the OADP Operator on the hub cluster in a namespace different from the backup component namespace, uninstall this version.

change #3

Update 

1.1.3.1.2. Enabling the backup operator

Change:

1. Manually install the cluster backup and restore operator. Enable the cluster backup and restore operator (cluster-backup). Edit the MultiClusterHub resource by setting the cluster-backup parameter to true. This installs the OADP operator in the same namespace with the backup component.

To:

1. Manually install the cluster backup and restore operator. Enable the cluster backup and restore operator (cluster-backup). Edit the MultiClusterHub resource by setting the cluster-backup parameter to true. If this hub cluster doesn't have the STS (AWS Security Token Service) option enabled,  the OADP operator is also installed in the same namespace with the backup component. For hub clusters where the STS option is enabled the user must install the OADP operator manually.