[Dev] log plots

[jbcaillau]

@ocots beautiful job for plots: https://control-toolbox.org/CTBenchmarks.jl/dev/assets/plots/robot_plot_time_vs_grid_size_7cfe439b.pdf
for such grid size x run times plots, (even) nicer to use log scale (x and y)

cc @AmielMetier @HediChennoufi