Add two console programs supporting 24-bit color.

[clort81]

Terminal Image Viewer
https://github.com/stefanhaustein/TerminalImageViewer

Chafa
https://github.com/hpjansson/chafa/

[kurahaupo]

@clort81 any chance you could submit a pull request, or otherwise send a patch?

How thorough is each one's support? Do they accept semicolons? colons? the extra colour-space parameter?