Create an InfiniBand cluster of whole h100-8 machines (preview)

Create an InfiniBand cluster. A cluster is 2 to 8 whole 8-GPU machines on a private InfiniBand network that we make for this cluster alone. Give chip "h100-8", nodes, and gpus. gpus must equal nodes x 8, and a mismatch never rounds. Each node is an ordinary h100-8 node named <name>-<rank>, and each node bills as an h100-8 node from the moment it is ready. The call never blocks. It returns the cluster in state "queued" with the rate. rate.cluster_per_min is the cost of all the nodes per minute. Preparation takes 10 to 45 minutes, and no node bills while the cluster is queued or preparing. Poll get_cluster until state is "running". Every node gets GMN_CLUSTER, GMN_CLUSTER_RANK, GMN_CLUSTER_SIZE and GMN_CLUSTER_MASTER_ADDR for torchrun. A cluster is all its nodes or none. If one node stops or is lost, the whole cluster ends and every disk is deleted. You cannot stop, delete or snapshot one node of a cluster. A call with the name of a live cluster and the same shape returns that cluster. network, clock_lock, profiling, scratch_gib and from_snapshot are not available for clusters. Clusters are a preview.