Add an administration control panel for the redirects created on rename

This issue concerns the feature added by XWIKI-3622 .

As an administrator of the wiki, I want to be able to see all the redirections that exist on the wiki and be able to clean them up, in case I want to reuse URLs or just clean test content from the wiki, for example. Also, I need this to be able to debug issues related to "page already exists" when renaming / copying / creating a page.
This is needed because there doesn't seem to be any other way to see these "pages" that are only redirect to other documents.
Also, this allows me, as an admin, to review the choices that were taken by regular content creators about redirects when they renamed pages.

As a developer/administrator , this allows me to clean unneeded pages from the wiki, and reach the simplest possible form that answers the needs of my wiki (see also the related issues for usecases).