Merge branch '6428-postfix-advertises-smtputf8-but-local-lmtp-delivery-fails-because-dovecot-does-not-support-it' into 'develop'

Resolve "Postfix advertises SMTPUTF8 but local LMTP delivery fails because dovecot does not support it"

Closes #6428

See merge request !1727

Resolve "Failed message symbol in auth.log"

Closes #6442

See merge request ispconfig/ispconfig3!1728

Resolve "Follow-up to #5588 - Change the required FQDN for "Sectigo / Comodo""

Closes #6456

See merge request ispconfig/ispconfig3!1729

Add delete button to some edit forms

See merge request ispconfig/ispconfig3!1362

Add an info tab for the client page #5372

See merge request ispconfig/ispconfig3!941

Convert zone_file_prefix and slave_zone_file_prefix functions to config option

See merge request ispconfig/ispconfig3!1376

Support configurable IMAP prefix per mailbox

Closes #5918

See merge request ispconfig/ispconfig3!1605

Option calculate Website Disk usage without Quota

See merge request ispconfig/ispconfig3!1704

Add script to add a new string to multiple translation files

See merge request ispconfig/ispconfig3!1721

Resolve "Create webdomain form lists domains that are already used"

Closes #6491

See merge request ispconfig/ispconfig3!1715

Move the email field higher up on the client form, #6494

Closes #6494

See merge request ispconfig/ispconfig3!1718

Deprecate ICQ, #6493

Closes #6493

See merge request ispconfig/ispconfig3!1717

Move dns wizard function to class

Closes #6496

See merge request ispconfig/ispconfig3!1720

Remove duplicate query

See merge request ispconfig/ispconfig3!1714

One was also without a placeholder

Resolve "Create a shell user - PHP Fatal error:  Uncaught TypeError: realpath()"

Closes #6472

See merge request ispconfig/ispconfig3!1713

Resolve "wrong databases are shown when selecting a server."

Closes #6480

See merge request ispconfig/ispconfig3!1712

Add Simplified Chinese translations for ISPConfig

Closes #6484

See merge request ispconfig/ispconfig3!1707

Extend Two-factor authentication

Closes #2558

See merge request ispconfig/ispconfig3!1594

fixes #6431 // make sure config file is deleted only during spamfilter_user event.

Closes #6431

See merge request ispconfig/ispconfig3!1674