noflo-ui: Adding graph inports and graph outports

[ERnsTL]

• currently it seems impossible to add graph inports and outports via the noflo-ui
• but if they are defined from the side of the runtime, then noflo-ui renders them correctly and interaction with them is fine.
• related issue: https://github.com/ERnsTL/flowd/issues/207

[ERnsTL]

• related issue: https://github.com/ERnsTL/flowd/issues/230

[ERnsTL]

• related issue on noflo-ui side: https://github.com/noflo/noflo-ui/issues/1342