[Visual] Add colors to the output of times depending on the speed

[Pyxels]

Don't know if this is something you'd like in your project, but I enjoy it. Feel free to close or critique, this is my first Rust PR.

This changes the color of the times outputted when running depending on the speed, to make it easiers to spot outliers and possible slow implementations. Since slow is subjective this feature disabled by default and I've added a command line flag -c or --color to enable the coloring.

Here are two screenshot with fast and slow solutions to illustrate the colors.

[remi-dupre]

Hi!

Thanks for your PR, this look gorgeous!

NB: as I see you enjoy colorful output you might like the automatic submission / checks I have started implementing in #29 (I'll attempt to merge it this week-end)

[remi-dupre]

Also, I think you can be more proud of your submission and make this an opt-out instead of an opt-in (--no-color instead of --color), maybe using more dim colors will help making it not too aggressive 🤔

[Pyxels]

I somewhat experimented with other color shades using .truecolor(r, g, b), but I found I quite liked the current colors. The current version with explicit colors also makes it easier to read for what that's worth.

If it's important I can look into it again.