Since the `orderEdges` function no longer consumes the graph, we can
finally make the restoration step separate - leading to more explicitly
stated boundaries as to where the graph is a DAG, and where it is not.
Also removed a few entities to avoid duplication in the full names:
- `yield::layout::sugiyama::LayoutOrientation`
-> `yield::layout::sugiyama::Orientation`
- `yield::layout::sugiyama::layout(...)`
-> `yield::layout::sugiyama::compute(...)`