vard cluster members might not use the same cluster size

[palmskog]

Since the Raft cluster size is set at runtime based on the passed parameters, strange errors can occur in vard if different cluster members use a different number of -node parameters. Even with cluster size set at compile time, this could be an issue if different deployments are compiled with different cluster size parameters.

One way to mitigate these kinds of errors is to let the shim perform some initial messaging before Raft communication starts, e.g., get confirmation that other nodes were configured with the same cluster size as the present node.