Support for image/graphics control sequences

[alexrp]

• Sixel graphics
  • https://en.wikipedia.org/wiki/Sixel
  • https://www.vt100.net/docs/vt3xx-gp/chapter14.html
  • https://www.arewesixelyet.com
• iTerm2 protocol
  • https://iterm2.com/documentation-images.html
  • https://iterm2.com/utilities/imgcat
  • https://wezfurlong.org/wezterm/imgcat.html
• kitty protocol
  • https://sw.kovidgoyal.net/kitty/graphics-protocol