Support Message Batching

[jeremydmiller]

It comes up often enough.

So if you have a handler like:

public static void Handle(Message[] messages), and you publish await bus.PublishAsync(new Message()), Wolverine does the aggregation for you. Needs to be able to track the success/failure of each message, plus the batched message. For right now, only support this for local queues.

cc @BrianVallelunga

[BrianVallelunga]

I'll add the comment that I think the aggregation needs to be by Tenant, also.

[jeremydmiller]

Oh, good point