Added prefetching to dovecot to halve database-queries
Added mdbox-creation for new Mailboxes in mdbox-format

Conflicts:
	install/tpl/debian6_dovecot-sql.conf.master
	install/tpl/debian_dovecot-sql.conf.master
	install/tpl/debian_postfix.conf.master
	install/tpl/fedora_dovecot-sql.conf.master
	install/tpl/fedora_postfix.conf.master
	install/tpl/gentoo_postfix.conf.master
	install/tpl/opensuse_dovecot-sql.conf.master
	install/tpl/opensuse_postfix.conf.master
	interface/web/admin/templates/server_config_mail_edit.htm
	server/cron_daily.php
	server/plugins-available/mail_plugin.inc.php
	server/plugins-available/postfix_server_plugin.inc.php

Master

See merge request !173

Conflicts:
	install/sql/incremental/upd_dev_collection.sql

- added intermediate SSL security profile (see https://mozilla.github.io/server-side-tls/ssl-config-generator/)
- TODO: admin option to choose between intermediate (default) and modern

Fixed a regex in ispconfig and apps vhost for nginx: https://www.howtoforge.com/community/threads/possible-bug-in-a-nginx-regex.68948/

DKIM: changed config-file-check to prevent saving the keys in the wrong file if a single amavis-config-file exists after upgrading to a "split-config"

Master

See merge request !172

Master

See merge request !171

Master

See merge request !169

Master

See merge request !168