New TurnKey Lighttpd Php Fastcgi version (17.0)

Updated all relevant Debian packages to Bullseye/11 versions; including PHP 7.4.
Provide predefined dh_params (via 'turnkey-make-ssl-cert' where relevant) as per RFC7919 - part of #1653.
Use default Debian PHP-FPM config (previously we supplied our own custom fastcgi service and setup).
Configure OCSP stapling (will only work once a valid cert is configured).
Enable HSTS by default (only effects HTTPS traffic - full implementation also requires HTTP redirect to HTTPS and valid cert).
Updated version of mysqltuner script.
Reorgnaise/refactor build code so there is now a dedicated lighttpd-php-mysql.mk and plan files. Generic/shared Lighttpd related build code now resides in common. (Development - should have no end user impact).
Note: Please refer to turnkey-core's 17.0 changelog for changes common to all appliances. Here we only describe changes specific to this appliance.