* also make factories more consistent by only offering
FlowGraph.create()
* also remove secondary (edge-based) FlowGraph.Builder DSL
* also improve naming for conversions from Graph to
Source/Flow/BidiFlow/Sink
* Remove name parameter (no overloads), naming is performed using `.withAttributes` or the new
convenience `.named`. Those adds the OperationAttribute.Name and also change the name of the
shape Inlet and Outlet.
* Remove Source/Sink parameter list for 0 parameter methods,
this allows usage of `Sink.head` instead of `Sink.head()`
