Add node numbers to the graphviz rendering in hugr-py

[CalMacCQ]

Would be nice to have the node numbers available in the graphviz rendering for hugr-py.

Consider this hugr graph.

Currently to get the node number associated with the exit node we need to print the output of Hugr.nodes() and compare with the diagram which isn't ideal

Node(0) NodeData(op=Module(), parent=None, metadata={})
Node(1) NodeData(op=FuncDefn(f_name='prepare_qubit', inputs=[Bool, Qubit], params=[]), parent=Node(0), metadata={})
Node(2) NodeData(op=Input(types=[Bool, Qubit]), parent=Node(1), metadata={})
Node(3) NodeData(op=Output(), parent=Node(1), metadata={})
Node(4) NodeData(op=OneQbGate(_enum=<_Enum.H: 'H'>), parent=Node(1), metadata={})
Node(5) NodeData(op=_NotOp(), parent=Node(1), metadata={})

[aborgna-q]

This should be added as an option in RenderConfig.