Added a server module for clients and a mail plugin.

- added a daily cronjob for stats creation in the installer.
- Fixed a bug in the spamfilter white / blacklist forms (thanks to satommy for reporting this)
- fixed ssl cert path in vhost templates/web_domain_ssl.htm
- fixed a bug in the apache plugin which prevented the copying of the standard error and index files.

- improved several functions in site module
- added server classes to restart services

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