Increase limits and add putenv to disabled functions (vulerability)

Potential security vulnerability:
<?php
putenv("LD_PRELOAD=/home/site.onion/libtest.so");
mail("test@localhost","hacked","you");

etc/systemd/system/nginx.service.d/custom.conf

@@ -1,6 +1,6 @@
 [Service]
 LimitNOFILE=100000
-TimeoutStartSec=300
+TimeoutStartSec=600
 ExecStop=
 ExecStop=-/sbin/start-stop-daemon --quiet --stop --pidfile /run/nginx.pid
 ExecStartPre=