Use `{cli}` package

[trevorld]

• Use {cli} instead of {crayon}
• 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
• File HTML conversion bug report upstream to {cli}?

[trevorld]

{cli} HTML conversion bug reported upstream with a minimal, reproducible example: r-lib/cli#752