* [FEM] add support for 3D recombinations
currently we only support surface recombinations but for some applications 3D recombinations are useful as well
* add support for the recombination algorithms
using a sensible algorithm is important to get useful results, see https://wiki.freecadweb.org/FEM_MeshGmshFromShape#Properties
where I described examples
- the property has the name "Element order" thus the dialog should use the same name to avoid confusions
-also uniform naming for the element dimension and remove the redundant "Mesh" (is already in the UI groupBox heading
- Gmsh has since a while 2 new mesh algorithms
- on the other hand the two algorithms ""Frontal Delaunay" and "Frontal Hex" are deprecated and not listed anymore in the docs: https://gmsh.info/doc/texinfo/gmsh.html#index-Mesh_002eAlgorithm3D
and indeed all attempts with these 2 algorithms fail