[2832] add datasrc spec support for 'cache-type'

src/bin/cfgmgr/plugins/datasrc.spec.pre.in

@@ -68,6 +68,12 @@
                                 "item_name": "name",
                                 "item_type": "string",
                                 "item_optional": true
+                            },
+                            {
+                                "item_name": "cache-type",
+                                "item_type": "string",
+                                "item_optional": true,
+                                "item_default": "local"
                             }
                         ]
                     }