TT#177600 Move SSL certificates under /etc/ngcp-config/shared-files/ssl

These are shared files across all PRO/Carrier nodes, but at the time
they were introduced we did not have the concept of a shared-files
subdirectory. All other such shared files have been moved over time to
that subdirectory, but this was still remaining behind. Let's move it
now for consistency, and so that its purpose is more clear.

Change-Id: I45c89245d36706dba5ed1fb47a8bf9124c390dae

templates/130_filesys-ngcp.yaml.tt2

@@ -65,6 +65,9 @@ file:
     contains: []
 
   /etc/ngcp-config/ssl:
+    exists: false
+
+  /etc/ngcp-config/shared-files/ssl:
     exists: true
     mode: "0750"
     owner: root