Add fpm config to log to stdout

in fpm.conf:
[global]
error_log = /proc/self/fd/2
log_level = error
log_buffering = no

in www.conf:
catch_workers_output = yes
decorate_workers_output = no
php_flag[display_errors] = off
php_admin_flag[log_errors] = on
php_admin_flag[fastcgi.logging] = off

Inspired by https://phil.lavin.me.uk/2023/02/php-fpm-log-errors-to-stderr-for-docker/