Switch Apache from mod_php to PHP-FPM

PHP-FPM is faster and isolates pools per site. Disable mod_php first, install FPM, enable proxy modules.

Disables the Apache mod_php handler and enables PHP-FPM with mod_proxy_fcgi instead. PHP-FPM allows separate per-site worker pools with different users and timeouts.

When you need this: When you need per-site PHP version isolation or better performance under load.