Use `{cli}` package

* [x] Use `{cli}` instead of `{crayon}`
* [x] Support user-customized `{cli}` color "palettes"
* [ ] Document relevant options such as palette options and number of colors
* [ ] Use `{cli}`'s HTML output instead of `{fansi}`'s
* [x] File HTML conversion bug report upstream to `{cli}`?