Use FFDHE 4096 group from RFC 7919 instead of "openssl dhparam"

[hardfalcon]

There are several instances where Froxlor 2.2.0 runs or advises the user to run openssl dhparam to generate a DH group when configuring TLS.

It is generally preferable to not use any custom-generated DH groups at all, and to simply use one of the FFDHE groups from RFC7919 instead:

https://wiki.mozilla.org/Security/Archive/Server_Side_TLS_4.0#Pre-defined_DHE_groups

Instances of openssl dhparam that I've found:

• https://github.com/froxlor/Froxlor/blob/2.2.0/lib/Froxlor/Cron/Http/Apache.php#L441-L447
• https://github.com/froxlor/Froxlor/blob/2.2.0/lib/Froxlor/Cron/Http/Apache.php#L754-L760
• https://github.com/froxlor/Froxlor/blob/2.2.0/lib/Froxlor/Cron/Http/Lighttpd.php#L273-L280
• https://github.com/froxlor/Froxlor/blob/2.2.0/lib/Froxlor/Cron/Http/Lighttpd.php#L756-L763
• https://github.com/froxlor/Froxlor/blob/2.2.0/lib/Froxlor/Cron/Http/Nginx.php#L399-L405
• https://github.com/froxlor/Froxlor/blob/2.2.0/lng/en.lng.php#L2148-L2151 and the other language files
• https://github.com/froxlor/Froxlor/blob/2.2.0/lib/configfiles/bookworm.xml#L3118 and the other distro config files (also note that this generates a 3072 DH group, whilst in all other instances, a 4096 bit DH group is generated/suggested).