Implement Flying Edges for structured cellsets with rectilinear and curvilinear coordinates

Depends on !3050 (merged) (will need rebase)

When Flying Edges was introduced to compute contours of a 3D structured cellset, it had a limitation to uniform data. This MR implements an alternative path through pass 4 (and 5 for some devices) to handle other type of coordinate systems. The Contour filter re-written in !3050 (merged) uses Flying Edges for these new supported cases accordingly.

Close #774 (closed)