Support listening on multiple ports

[hallfox]

This extends the broker config to support listening to connections on multiple ports. This lays the groundwork for future extensions that will be added to TcpInterfaceListener. The broker will behave the same without the listener config, but with the listeners added the broker will open new listen operations for each one, ignoring the port field in the networkInterfaces. We also added an extra component for validating these new configs.