Docs on how we handle aws permissions

DoD:

A  recurrent question is how iam works in hypershift.

We should document in https://hypershift-docs.netlify.app/ or https://github.com/openshift/enhancements/tree/master/enhancements/hypershift how we handle permissions in AWS

https://redhat-internal.slack.com/archives/C02LM9FABFW/p1674631577577369