www/tt-rss: Run ttrssd as ttrssd user and move data to /var

[dereks_lifeofadishwasher.com]

Summary

• Create a ttrssd user and group to run ttrssd.
• Move log file to /var/log/tt-rss directorie.
• Move pid files to /var/run/tt-rss directorie.
• Move on disk data to /var/tt-rss/.

Test Plan

Clear our exisiting www/tt-rss install, install updated port.
Confirm writing to tne locations from config.php and local/www/tt-rss isn't being used.
See ttrssd running as non-www user.

[dereks_lifeofadishwasher.com]

Rebased on main

[dereks_lifeofadishwasher.com]

Rebase on main for tt-rss-g20250704 0df0ed7b50dc182