Make changes to https://docs.okd.io/latest/backup_and_restore/application_backup_and_restore/installing/about-installing-oadp.html#oadp-s3-compatible-backup-storage-providers-supported

Proposed Documentation Updates

• Change the heading: On the page "About installing OADP," change the heading "Supported backup storage providers" to "Certified backup storage providers"

• Clarify the support statement: Add a note to the section that clarifies the new support policy. The note should state that Red Hat will provide support for OADP on any S3-compatible storage, but support will stop if the S3 endpoint is determined to be the root cause of an issue.