Package configuration and alias for Buku

[arcticicestudio]

Buku provides the BUKU_COLORS environment variable to allow users to define a custom color scheme. It follows the same principle like the LSCOLORS environment variables of the BSD ls command.
The five letters represent the colors in ordered form of

• index
• title
• url
• description/comment/note
• tag

See the GitHub repository wiki page about how to customize colors for details about available letters and their meaning.

Next to this a shortcut alias bk should be added to simplify the usage commands.