www/chawan: new port: A text-mode web browser and pager

Chawan is a text-mode web browser and pager for Unix-like systems, with a focus
on implementing modern web standards while remaining self-contained, easy to
understand and extensible.

It includes functionality like CSS, inline images inside the terminal, and
JavaScript through a small, independent browser engine.

Most of Chawan has been developed from scratch in the memory-safe Nim
programming language.

WWW: https://chawan.net

PR: 288598
Reported by: Al Hoang <hoanga@gmail.com> (new maintainer)