Consider supporting gradients

[Mathias-Boulay]

Hello there, I found myself wanting to use gradients for part of my CLI.
In my case, it was the ProgressBar

I desired something like the following:

Since console doesn't support gradients, I took the liberty of creating my own implementation for it (hence the image produced beforehand)

Should I clean up my work and make a PR, or is it not planned to support such a case ?

[djc]

I'm open to reviewing code for this assuming the complexity is pretty self-contained. FWIW I can also review PRs in console so if it makes more sense to keep some of your code in that crate, suggest spreading it across the crates if/where that makes sense.

[Mathias-Boulay]

Well yeah the code changes were in console only but the color capabilities were also bolstered in the readme of this repository.

I'll probably do a PR "soon" on console then

[Mathias-Boulay]

@djc Initial PR done, let's move the discussion over there.
console-rs/console#233