Review the MTU allowed to be used in OCP.

Initially the cluster is set the MTU 8091 for the cluster network/overlay due the discovery of the machine network interface.

The bug OCPBUGS-6800 describes that the MTU that should be used on Local Zone nodes to talk with nodes in the regular zones is 1300 (need to remove the overlay network overhead).

The goal of this card is to validate the values described on the AWS docs, and make sure we tested all the "maximum" MTU allowed to run on the overlay network.