Overall 'server-state' flag on the Host Controller

This is for consideration; we need to see if it makes sense.

Request is for an attribute on the HC that indicates aggregate 'server-state'. The desire is to know when all servers are available, and thus it is safe to invoke management ops knowing all servers will receive them.

The only reason a server wouldn't receive an op is if it is started in a non-blocking mode, so the server gets its config but then hasn't connected with the HC and therefore won't get update operations. Starting the server in blocking mode will avoid this situation (as could changes to how we start servers, to make it more like how a slave HC registers with the master HC). So, before doing this let's first look at how to reduce/eliminate the use case for it.

Also to consider when looking at this is how to represent servers in things like "restart-required" state in this overall aggregate 'server-state'.