BirdNET-Pi's installer runs PHP-FPM as the caddy user, so getenv('HOME')
resolves to /var/lib/caddy - not the install user's home. Every path
constructed from getenv('HOME') was broken on first install.
PHP resolves __DIR__ through the install_services.sh symlink to the
realpath ($HOME/BirdNET-Pi/avian/api), so dirname(__DIR__, 2) = the
BirdNET-Pi install root and dirname(__DIR__, 3) = the user's home.
Works under any username because nothing is hardcoded.
Also fixed birdnet-api.php's DB_PATH which walked one level too far
(used , 3) - the BirdNET-Pi root is , 2).
Twarner491
9ea3249f9d