fix: nginx error when loading the site

From https://stackoverflow.com/a/68314973:

> Increasing the fastcgi_buffer_size in nginx config helped, but it
seems more like a suppression the problem, not a treatment.

> A better solution is to disable php-fpm to send logs by FastCGI. Found
it can be made by setting fastcgi.logging=0 in php.ini (by default it is
1). php docs.

> After changing it to 0, the problem goes away and nginx logs looks much
cleaner docker logs nginx:

Fixes: #463

tools/docker/images/php/configs/php.ini

@@ -1,2 +1,3 @@
 date.timezone=UTC
 expose_php=Off
+fastcgi.logging=0