Base16 support

[clach04]

Build upon:

• Base24 support - https://github.com/tinted-theming/ #25

Implement input/output support for:

• https://github.com/tinted-theming/home/blob/main/styling.md
• Original https://github.com/chriskempson/base16/blob/main/styling.md
  • aka Legacy https://github.com/tinted-theming/home/blob/main/styling.md#legacy-ayu-darkyaml

Support mapping normal colors to bright:

1. as-is - i.e., copy
2. brightened/lightened