misc/navi: Add new port

navi allows you to browse through cheatsheets (that you may write yourself or
download from maintainers) and execute commands. Suggested values for arguments
are dynamically displayed in a list.

  - it will spare you from knowing CLIs by heart
  - it will spare you from copy-pasting output from intermediate commands
  - it will make you type less
  - it will teach you new one-liners

https://github.com/denisidoro/navi