Make the "redirect" option on page rename configurable

Actually, this option (added as XWIKI-3622) is interesting mostly for the editorial pages (content created by content creators).

As a developer, when I develop my applications and I rename various documents (because all code is stored in documents), I don't want nor need redirect for them. In addition, in the current implementation, this creates bloat on the wiki (too many unused documents). Also, creating redirects for renamed pages can prevent me from seeing properly when I am breaking links with my renames, in development phase.

As an administrator of the wiki, I might want to switch from one default rename to another: in a preparation phase for the wiki, when I am creating the general setup of a wiki which is not yet open to contributors, I don't need redirects. I would only need redirects once I opened my wiki to contributors and renames can break somebody's bookmarks. Also, having redirects in the preparation phase prevents me from creating the simplest possible wiki that answers my needs (lots of redirects will be created). Note that redirects are not deleted on page deletion, so all the test content that was renamed will persist as well.

Multiple options exist:

• check the box by default only for simple users
• add a user preference for the checkbox
• add a system preference for the checkbox , in administration or in a config file (this would be less flexible though)