Make PHP FPM pool configurable

templates/php_pool.conf

@@ -7,11 +7,11 @@ listen = 127.0.0.1:{{ item.jail.port }}
 
 ; Process manager
 pm = dynamic
-pm.max_children = 10
-pm.start_servers = 4
-pm.min_spare_servers = 2
-pm.max_spare_servers = 6
-pm.max_requests = 2000
+pm.max_children = {{ php_fpm_max_children }}
+pm.start_servers = {{ php_fpm_start_servers }}
+pm.min_spare_servers = {{ php_fpm_min_spare_servers }}
+pm.max_spare_servers = {{ php_fpm_max_spare_servers }}
+pm.max_requests = {{ php_fpm_max_requests }}
 
 ; Environment variables
 env[HOSTNAME] = {{ inventory_hostname }}