Record the sequence of operators applied

[sebmestrallet]

In the GUI of the automatic_polycube app, several buttons for labeling operators are printing what happened :

// app/automatic_polycube.cpp draw_object_properties()
if(ImGui::Button("Fix invalid corners (as much as possible)")) {
	size_t nb_invalid_corners_processed = fix_as_much_invalid_corners_as_possible(mesh_ext_,labeling_,lg_);
	fmt::println(Logger::out("fix_labeling"),"{} invalid corners processed",nb_invalid_corners_processed); Logger::out("fix_labeling").flush();
	update_static_labeling_graph(allow_boundaries_between_opposite_labels_);
}

but when gui=false, almost no high-level info is printed...

A quick solution is to print homogeneous messages, with the GEO::Logger, inside src/labeling_operators_on_invalidity.cpp auto_fix_validity() and src/labeling_operators_on_distortion.cpp auto_fix_monotonicity().

A better solution is to list applied operators, with their parameters and outcome, as a structured data to export (as JSON for example).