Ports should be tracked by a unique identifier

[brizzbuzz]

Reference the issue I opened and closed earlier #723

It seems unwise to store a node models ports by their name, as for many possible use cases, this is not a unique identifier

addPort(port: PortModel): PortModel {
  port.setParent(this);
  this.ports[port.getName()] = port;
  return port
}