Check tapicero heartbeat (Bug #6556)

In order to assure tapicero is still working, we need to monitor
/var/log/syslog for the last tapicero log msg, which should not be older
than the last check_mk_agent run (every 2 mins atm).
Merge branch '6556_tapicero_heartbeat' into develop
Merge remote-tracking branch 'leap/develop' into pixelated/develop