Description of problem:

In the main landing page for Submariner, add a note saying that Submariner is not supported on all the infrastructures and for more details they can take a look at the support matrix.

As an example for ACM 2.8:
Landing page: https://access.redhat.com/documentation/en-us/red_hat_advanced_cluster_management_for_kubernetes/2.8/html/networking/networking#submariner
Support matrix: https://access.redhat.com/articles/7006295