Smooth surface definition using arbitrary boundries

[adam-urbanczyk]

It would be nice to expose BRepFill_Filling or GeomPlate_BuildPlateSurface and allow users to define smooth/organic surfaces.

[adam-urbanczyk]

Nice examples: https://neweopencascade.wordpress.com/2019/03/15/build-constrained-surfaces-with-brepoffsetapi_makefilling-part-i/

[adam-urbanczyk]

Solved by #253