XWIKI-8735: Locked Logging administration panel with useless "force edit" link
XWIKI-8747: Occasional stacktrace in the console when using the Applications section in Administration (trying to get the page lock with js)
* Created a DocumentLock JavaScript class to handle the edit lock for a given document.
* Change ConfigurableClass to use the new DocumentLock.
* Add method to XWiki.EntityReference to extract the value of reference.