[php-src] Issue #13110: Add option to hide Environment Variables from $_SERVER

Issue: https://github.com/php/php-src/issues/13110 Author: ggedde ### Description I am looking for a way to hide Environment Variables from $_SERVER or from all Global Arrays. I would prefer to secure my environment variables as much as possible and make them explicit when using. I only require getenv('my_env_var'); I do not want or need $_SERVER['my_env_var'] or $_ENV['my_env_var']. There are many third-party tools and libraries that might expose $_SERVER in logs or debugging. Also if the code is compromised dumping $_SERVER is very easy. This could be mitigated by encrypting Environment Variables, but I would also like to make accessing them very explicit. Currently I can set clear_env to yes and change variables_order to "GPCS" and ignore "E" to remove $_ENV, but I can't remove "S" as that is needed for REMOTE_ADDR, etc. It would be nice to have another php config option to do that and have that option accessible from php-fpm config as well like clear_env or variables_order Maybe something like expose_env. Default is yes, but can be set to no. no should remove it from $_SERVER as well as $_ENV or any other Global data. Bonus points if no can also remove it from, errors, functions (like debug_backtrace), etc. Thanks