Feature request: hex mesh local refinement

[danasolav]

Would be great to have this capability. Optional algorithms are described here:

https://www.researchgate.net/profile/Mamtimin-Geni/publication/242402318_Effective_Adaptation_of_Hexahedral_Mesh_using_Local_Refinement_and_Error_Estimation/links/564ad9e908ae127ff986cde0/Effective-Adaptation-of-Hexahedral-Mesh-using-Local-Refinement-and-Error-Estimation.pdf

https://coreform.com/cubit_help/mesh_generation/mesh_modification/mesh_refinement.htm

https://imr.sandia.gov/papers/imr20/Paudel.pdf