[new] multimedia/ytfzf

Hi,

cc solene@ and luffy20201@protonmail.com (initial request to create this
port)

Proposal to import a new port multimedia/ytfzf for ytfzf tool
https://github.com/pystardust/ytfzf

ytfzf is a shell script that helps you find Youtube videos (without API)
and opens/downloads them using mpv/youtube-dl.

Initial port for version 2.6.0:
- no build, only an install stage to copy script, manpages, example
for config and copy addons
- patch script for addons directory => substitute VAR for
${TRUEPREFIX}
- RUN_DEPENDS for jq, curl, fzf, multimedia/mpv and www/yt-dlp
- no dependency for ueberzugpp (no port for OpenBSD)

Basic tests searching Youtube videos and displaying the list of results
with fzf.

Please test, comments welcome and commit if OK.

Laurent