www/libreddit: import package from wip.

Packaged by @pin with minor modifications by me.

Libreddit is a portmanteau of libre (meaning freedom) and Reddit.
It is a private front-end like Invidious but for Reddit.
Browse the coldest takes of r/unpopularopinion without being tracked.

- Fast: written in Rust for blazing-fast speeds and memory safety
- Light: no JavaScript, no ads, no tracking, no bloat
- Private: all requests are proxied through the server, including media
- Secure: strong Content Security Policy prevents browser requests to Reddit

(vins)