Currently there is no support for managing multiple hypervisors and their included OpenShift clusters. Users should be able to provision multiple EC2 instances and install OpenShift on each of them independently.

Reasonable defaults are expected to preserve backwards compatibility

 
Acceptance Criteria

• Usage for single hypervisor/cluster doesn't change
• When provisioning a second hypervisor/cluster, instead of erroring out, user will be given the option to create a second, separate one. Same for third, fourth, etc
• Users can run any of the make hypervisor and cluster commands with no variable, which will default to the first provisioned cluster, or by setting a CLUSTER_ID variable to a certain value, which will make the command affect that cluster/hypervisor
• No explicit tooling support for external hypervisors, but Claude should be able to guide the user to filling enough scaffolding for this to work
• Instance folder, cluster state json and inventory.ini will need to be grouped in a directory per cluster-id, since those have the state of the hypervisor/cluster pair
• Adapt all existing code to work with the above new per-cluster directory
• Add new make commands to list clusters and to let the user select a default cluster to work with