copy install/tpl/apache_ispconfig.conf.master to server/conf/apache_ispconfig.conf.master

If you add/remove server IPs the file `/etc/apache2/sites-available/ispconfig.conf` gets recreated and it is missing the alias for Let's Encrypt ACME challenges. Copying over the current install template fixes that. 

Maybe one could remove this template duplication completely by using `server/conf/apache_ispconfig.conf.master` in the install process?

The `Header set Content-Type "text/plain"` was only in `server/conf/apache_ispconfig.conf.master` and not in `install/tpl/apache_ispconfig.conf.master` – is it necessary?

See merge request !463

fixed umount backup-dir



See merge request !464

If you add/remove server IPs the file `/etc/apache2/sites-available/ispconfig.conf` gets recreated and it is missing the alias for Let's Encrypt ACME challenges. Copying over the current install template fixes that. 

Maybe one could remove this template duplication completely by using `server/conf/apache_ispconfig.conf.master` in the install process?

The `Header set Content-Type "text/plain"` was only in `server/conf/apache_ispconfig.conf.master` and not in `install/tpl/apache_ispconfig.conf.master` – is it necessary?

handle bash script overwrites during update.  fixes #4227



See merge request !461

Fixes wrong query errors (fixes #4231, #4240)



See merge request !459

Fix xfs_quota

Fix xfs_quota:
 - Replace "-g" with "-u" because username is is used
 - Set the path for the timer command

See merge request !458

truncate sys_session during update



See merge request !455

fixed placeholder



See merge request !454

The cipher suites are only set now for ISPConfig's own vhost, the intermediate security profile from Mozilla is used here.

Merged language files.

use php filter_var database remote-ip (#4215)



See merge request !453

Added fields user_config and user_type to the ftp_user table.