Tetrahedral remeshing - make each step optional

[janetournois]

Summary of Changes

This PR adds named parameters to make different remeshing steps optional
New named parameters :

• do_split
• do_collapse
• do_flip
• nb_smoothing_operations

note nb_flip_smooth_operations was already there

Do you @sloriot @MaelRL think they should be documented, maybe in an "Advanced NP" section?

Release Management

• Affected package(s): Tetrahedral_remeshing
• Feature/Small Feature (if any):
• Link to compiled documentation (obligatory for small feature) wrong link name to be changed
• License and copyright ownership: unchanged

[lrineau]

Now the following code triggers a compilation error:

    CGAL::tetrahedral_isotropic_remeshing(
          cdt,
          3 * bbox_max_span,
          CGAL::parameters::number_of_iterations(1).nb_flip_smooth_iterations(20)
          .remesh_boundaries(false));

include/CGAL/tetrahedral_remeshing.h:585:7: error: non-constant-expression cannot be narrowed from type 'int' to 'std::size_t' (aka 'unsigned long') in initializer list [-Wc++11-narrowing]

   585 |       choose_parameter(get_parameter(np, internal_np::nb_flip_smooth_iterations), std::size_t{3})};
       |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A possible fix is to use 20u (of type unsigned int) instead of 20 (type int) as the value passed to nb_flip_smooth_iterations. I am not sure why. And I do not know why the parameter CGAL::parameters::number_of_iterations(1) is fine.