added backupninja support, by default is disable

metadata/service/support.yml

@@ -11,3 +11,5 @@ parameters:
         enabled: true
       sphinx:
         enabled: true
+      backupninja:
+        enabled: false

salt/meta/backupninja.yml

@@ -0,0 +1,5 @@
+backup:
+  salt:
+    fs_includes:
+    - /srv/salt/reclass/nodes/_generated
+    fs_excludes: []