Shows last ip that was used to login successfully with this useraccount.
Logins from admins using loginAs are ignored

Implementiert Issue #4357
Zeigt die IP-Adresse des letzten erfolgreichen Logins auf dem Dashboard an.
Verändert die gespeicherte IP-Adresse nicht, wenn man sich via "Einloggen als" angemeldet hat.

Needed Database-Changes:

ALTER TABLE `sys_user` ADD `last_login_ip` VARCHAR(50) NULL AFTER `lost_password_reqtime`;
ALTER TABLE `sys_user` ADD `last_login_at` BIGINT(20) NULL AFTER `last_login_ip`;

Tested/Working on Ubuntu 16.04 LTS

- Fixed mailuser login

This implements ispconfig/ispconfig3#3644

Fixed login as

- Implemented session message system (template modifications pending)
- Updated ISPC SVN version number to 3.0.5

Just mailuser fixed

- install: touch auth.log
- login: write success/fail to auth.log
- cron: log rotation for auth.log

fail2ban compatible login log (no permissions for /var/log/ispconfig/login.log) - to be fixed! (FS#2244)

- Fixed: FS#2292 - monitor_tools.inc.php uses /var/vmail and not the mail directory specified in server config
- Changed code comment in login/index.php file.

Fixed: Notice: Undefined variable: maintenance_mode_error in /usr/local/ispconfig/interface/web/login/index.php on line 238