Work with the locations of an item
 To work with item locations you first need to get a reference to the ContentLocationService, which is your entry point for retrieving the information about the locations.
 You get a reference to the service in the following way: 
 var clService = SystemManager.GetContentLocationService();
 Information provided by the ContentLocationService
 The ContentLocationService provides you with an enumeration of IContentItemLocation objects – these are all the locations where the specified item can be opened.
 Information provided by the IContentItemLocation interface
 IContentItemLocation interface provides information about a specific content item location. You can get the ItemAbsoluteUrl for this location. If this location is the default (canonical) – this is the canonical URL of the item. The interface contains information for the PageId, SiteId, and a Boolean value indicating, if this location is the default (canonical) one.