bevy_color: Add Tailwind palette (#12080)

# Objective

Give Bevy a well-designed built-in color palette for users to use while
prototyping or authoring Bevy examples.

## Solution

Generate
([playground](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=f7b3a3002fb7727db15c1197e0a1a373),
[gist](https://gist.github.com/rust-play/f7b3a3002fb7727db15c1197e0a1a373))
consts from [Tailwind](https://tailwindcss.com/docs/customizing-colors)
(mit license) json.

## Discussion

Are there other popular alternatives we should be looking at? Something
new and fancy involving a really long acronym like CIELUVLCh? I'm not a
tailwind user or color expert, but I really like the way it's broken up
into distinct but plentiful hue and lightness groups.

It beats needing some shades of red, scrolling through the [current
palette](https://docs.rs/bevy/latest/bevy/prelude/enum.Color.html),
choosing a few of `CRIMSON`, `MAROON`, `RED`, `TOMATO` at random and
calling it a day.

The best information I was able to dig up about the Tailwind palette is
from this thread:
https://twitter.com/steveschoger/status/1303795136703410180. Here are
some key excerpts:

> Tried to the "perceptually uniform" thing for Tailwind UI. 
> Ultimately, it just resulted in a bunch of useless shades for colors
like yellow and green that are inherently brighter.

> With that said you're guaranteed to get a contrast ratio of 4.5:1 when
using any 700 shade (in some cases 600) on a 100 shade of the same hue.

> We just spent a lot of time looking at sites to figure out which
colors are popular and tried to fill all the gaps.
> Even the lime green is questionable but felt there needed to be
something in between the jump from yellow to green 😅

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>

crates/bevy_color/src/palettes/mod.rs

@@ -2,3 +2,4 @@
 
 pub mod basic;
 pub mod css;
+pub mod tailwind;