Add zend opcache template to enable it

Add zend opcache template to enable it. This template is based on the opcache.ini in the php54-php-pecl-zendopcache-7.0.2-4.el6.x86_64.
If we want to enable OPCache for PHP 5.3, then we need a logic to prevent conflicts with `APC.enable_opcode_cache=1`, which is set by default in PRODUCTION environment.