ext5migrate: replace deprecated call Ext.ModelMgr.create()

Ext.ModelMgr.create() was removed in 5.*
The recommended way to create a new instance is to call Ext.create()
Ext.create() does not take a "id" argument, however it sets
the id of the instance to the id  of the config object given
to the Ext.create() call.

www/manager5/tree/ResourceTree.js

@@ -114,7 +114,7 @@ Ext.define('PVE.tree.ResourceTree', {
 		}
 	    }
 	}
-	var child = Ext.ModelMgr.create(info, 'PVETree', info.id);
+	var child = Ext.create('PVETree', info);
 
         var cs = node.childNodes;
 	var pos;