Waiting for ROSA cluster state to be ready

[willgarcia]

Currently the provisioning of a ROSA cluster does not wait for it to be in a ready state.

This means that the terraform apply command is completed successfully while the cluster can be in waiting or installing state.

In an automation context, it would be helpful to wait for the cluster to be ready in order to be able to programmatically chain actions (eg, install cluster add-ons).