Merge branch 'develop' into 'develop'

.gitlab-ci.yml

install/dist/tpl/gentoo/apache_ispconfig.vhost.master

install/lib/installer_base.lib.php

install/tpl/apache_apps.vhost.master

install/tpl/apache_apps.vhost.master

install/tpl/server.ini.master

interface/web/admin/form/server_config.tform.php

interface/web/admin/form/users.tform.php

interface/web/admin/lib/lang/en_server_config.lng

interface/web/admin/templates/server_config_dns_edit.htm

interface/web/client/form/client.tform.php

interface/web/login/index.php

server/conf/apache_apps.vhost.master

server/conf/apps_php_fpm_pool.conf.master

server/conf/vhost.conf.master

server/lib/classes/letsencrypt.inc.php

server/plugins-available/bind_plugin.inc.php