XWIKI-13935: Add atomic store API for document renames

  * Add new method in store for atomic rename
  * Move methods from XWikiDocument to XWiki for rename
  * Use a fallback on old copyAndDelete rename if the option to use
    atomic rename is not set to true as a security measure
  * Move XWikiDocumentTest#rename to XWikiTest and test both new and old
    rename
  * Update refactoring to use a real rename method and not copy/delete.
  * Document new option to switch off atomic rename if needed.
  * Change the way XWikiSpace are loaded in HibernateStore and adapt the
    class to allow setting its store.
  * Move old deprecated rename methods using strings to legacy
  * Create new utility methods in Document API that uses references
    instead of String for backlinks and children
  * Create a new scenario for moving a page to a subwiki.