Proposal for changes to the API to support BYO infra for hypershift on AWS

So we need infra information to satisfy these requirements:

1. Know where to place the machines, with the proper subnet, instance profile, and security groups.
   • Question for this ... do we always want to have a default nodepool generated from the HostedCluster? or are we going to eventually require you to create those resources separately?
2. Create a cloud configuration file so that the in-tree AWS provider in the KCM can manage load balancers, pvs.
3. Setup the openvpn config so that machine IPs can be routed through the VPN.

References

https://github.com/openshift/hypershift/pull/65 
https://github.com/openshift/hypershift/pull/38

https://github.com/openshift/hypershift/pull/82