TT#72351 Install ngcp-system-tests by default

This is just another part of our monitoring, so let's make it easy to
use after installation and in production environments.

Change-Id: Ie30680e2dd48c9b5cf6419a5cf770c253b3d8cf9

debian/control

@@ -365,6 +365,7 @@ Depends:
  ngcp-rtpengine,
  ngcp-snmp-agent,
  ngcp-status,
+ ngcp-system-tests,
  ngcp-system-tools-pro,
  ngcp-upgrade-pro,
  ngcp-vmnotify,
@@ -452,6 +453,7 @@ Depends:
  ngcp-rtpengine,
  ngcp-sems,
  ngcp-status,
+ ngcp-system-tests,
  ngcp-system-tools-ce,
  ngcp-upgrade-ce,
  ngcp-vmnotify,
@@ -556,6 +558,7 @@ Depends:
  ngcp-rtpengine,
  ngcp-snmp-agent,
  ngcp-status,
+ ngcp-system-tests,
  ngcp-system-tools-pro,
  ngcp-upgrade-pro,
  ngcp-vmnotify,