Eliminate Waltz admin protocol

[whynick1]

Because we decide to add 32 (or 64) bit Flags to distinguish a regular request from an admin request, like

public HelloRequest(String greeting, Flags flags) {
 this.greeting = greeting;
 this.flags = flags;
}

admin protocol is not needed anymore. So, we want to

1. eliminate Waltz admin handler and admin port
2. instead use Flags to replace existing admin related request.

[whynick1]

1. eliminate Waltz admin handler and admin port

^ For that part, we should make sure we include SRE in this decision. For dropwizard services they are moving TOWARD having an admin port. Given that we don't have full AuthN/AuthZ, we need to be thoughtful about this.

[whynick1]

This requires Riff change.