[Tree] Show top-level node of tree, except root

Show top-level nodes when instantiating tree views, except for
the Root object. Supports Add dialogs in WTD-922.

platform/commonUI/general/bundle.json

@@ -150,12 +150,17 @@
         "representations": [
             {
                 "key": "tree",
-                "templateUrl": "templates/tree.html",
+                "templateUrl": "templates/subtree.html",
+                "uses": [ "composition" ],
                 "type": "root",
                 "priority": "preferred"
             },
             {
                 "key": "tree",
+                "templateUrl": "templates/tree.html"
+            },
+            {
+                "key": "subtree",
                 "templateUrl": "templates/subtree.html",
                 "uses": [ "composition" ]
             },

platform/commonUI/general/res/templates/tree-node.html

@@ -17,7 +17,7 @@
               ng-show="toggle.isActive()"
               ng-if="model.composition !== undefined">
 
-            <mct-representation key="'tree'"
+            <mct-representation key="'subtree'"
                                 ng-model="ngModel"
                                 mct-object="treeNode.hasBeenExpanded() && domainObject">
             </mct-representation>