handle Debian start scripts by dh_installinit

the Debian package build mechanism
(used for Debian, Ubuntu, Univention)
offers support functions to handle daemon init scripts.
This patch uses this mechanism.
It also adapts the behavior of RPM packages to be identical to DEB packages.
Changed behaviour:

   bareos-dir, bareos-sd and bareos-fd are enabled on install/update
     On install, daemons are normally not configured
     and therefore automatic activation often not useful.
     However, this the the default behavior of Debian
     and therefore we configured it in this way.

   bareos-fd is started/restarted on install/update
     bareos-dir and bareos-sd are not restarted, to prevent canceling running jobs.

   bareos-dir, bareos-sd and bareos-fd are stopped on deinstall

   When doing an install from source (make, make install) on Debian,
     init scripts will not be installed.
     An extra call "make install-autostart" is required.

Signed-off-by: Marco van Wieringen <marco.van.wieringen@bareos.com>
Rebuild configure.