Default Sideset IDs Assignment for Hole Surfaces in NetGenMeshInterface

[miaoyinb]

NetGenMeshInterface is capable of generating 3D Tet meshes with internal "holes" based on the input hole meshes. However, no default sidesets are assigned to the surfaces of these holes. It would be helpful if such default sidesets could be generated by NetGenMeshInterface.

For example, 1,2,3,...,N can be assigned to the surface of the N holes, respectively.