Client/Tools/FreeBSDInit: rework the whole tool

The old FreeBSDInit tool was basically a stub. So this is a complete rewrite. The new FreeBSDInit tool uses the service and sysrc tools to manage the FreeBSD rc.d services. There are no hardcoded paths to /usr/local/etc/rc.d/ anymore and the service tool handles rc.d scripts in /etc/rc.d/ as well.

Additional to that, the new tool also gathers information about extra services that are enabled (using service -e) and can enable new services with sysrc. This is a frontend for /etc/rc.conf and therefore changes that file.