message: Clean include from .cpp
diff: #include <ringmesh/geomodel/geomodel_mesh_entity.h>
  -#include <stack>
  -
  #include <ringmesh/basic/geometry.h>
  #include <ringmesh/geomodel/geomodel.h>
  #include <ringmesh/geomodel/geomodel_geological_entity.h>
  -#include <ringmesh/geomodel/geomodel_validity.h>
  #include <ringmesh/mesh/mesh_builder.h>
  