Add ANSI Colours into CSS output

[TimoNotThy]

In the style guide bold colors are mentioned but they're not available in the css palette. Could they be added like --ctp-mocha-ansi-red for

[unseen-ninja]

Personally I've treated the ANSI colours as something that is not meant to be used in regular syling hence I figured that we don't really need it in the CSS and software pallettes. Tho I might be wrong. I guess technically it also doesn't hurt to have them in there?
What are your thoughts on this @sgoudham, @backwardspy?

[sgoudham]

It was on my mind to implement during #98 but I was pretty focused on the last minute edits that we did that I forgot to update the CSS/SCSS palettes before merging.

Whether or not there's a real use case for it, it's pretty trivial/simple to implement so happy to add it. We will most likely use it down the line for representing our style guide in a web based format... whenever that happens ;) @unseen-ninja