Added a third parameter to $app->log() function in server part to turn off logging to database and use this option in mysql lib to not log any server side SQL errors to the database.

Allow for serial to be increased when deleting any record in the zone

See merge request ispconfig/ispconfig3!773

- Fixed #5027 add support for PHP 7.1 and 7.2 on nginx servers in apps vhost.
- suppress some warnings in simplepie.inc.php

add option to remote-api to increase the serial (Fixes #4930 #4806)

See merge request ispconfig/ispconfig3!772

Raised IDS block levels and set warn level to block level to avoid that the log gets filled with warnings.

Reseller is able to see a list of all clients and not just of his own clients in select field in the head of domain list when domain module is active.

add mail-relay and mail-transport to resync

See merge request ispconfig/ispconfig3!763

add "locked" to clients list

See merge request ispconfig/ispconfig3!761

Resolve "Very slow MySQL Queries in mail_[user|forward|alias]_edit.php"

See merge request ispconfig/ispconfig3!757

See issue #4984

don't expose the specific ISPConfig version number through the title html-tag

See merge request ispconfig/ispconfig3!756

- fixed backups not downloadable on multiserver slave, fixes #4973

. Thank's to Oliver for the fix.