orchestrator: move broker component as orchestrator

We can have one main subcomponent per component. We don't do that for
the inlet component as there is more configuration.

orchestrator/config.go

@@ -0,0 +1,10 @@
+package orchestrator
+
+// Configuration describes the configuration for the broker.
+type Configuration struct {
+}
+
+// DefaultConfiguration represents the default configuration for the broker.
+func DefaultConfiguration() Configuration {
+	return Configuration{}
+}