Resolve "Change default URL of phpmyadmin and webmail to apps vhost"

Closes #6415

See merge request ispconfig/ispconfig3!1665

add mail_relay_domain API functions #6399

See merge request ispconfig/ispconfig3!1644

Fix var name issue crippling vhost_rewrite_v6?

Closes #6414

See merge request ispconfig/ispconfig3!1663

closes #6414

Update .gitlab-ci.yml file to account for beta releases

See merge request ispconfig/ispconfig3!1662

De lang updates

See merge request ispconfig/ispconfig3!1660

Merge branch '6411-add-ubuntu-22-04-specific-config-settings-and-version-detection-code' into 'develop'

Resolve "Add Ubuntu 22.04 specific config settings and version detection code"

Closes #6411

See merge request ispconfig/ispconfig3!1661

Resolve "Use predefined DH params file to speed-up installation"

Closes #6390

See merge request ispconfig/ispconfig3!1659

Use central predefined 4096 bit DH params file (from Mozilla https://ssl-config.mozilla.org/ffdhe4096.txt ) instead of creation one via openssl command to speed up the installation. Thank you to @ahrasis for code suggestions.