Allow temporary "sudo"-like admin privileges

Users sometimes need admin or programming privileges in the wiki (e.g. to save a page containing code), but in general a smaller set of privileges suffices. Bob (without programming rights) might write a page containing groovy, and then to get this working would have to log out and login as a user with higher privileges (bobAdmin, say) to edit the page and re-save the page to allow the code to run. This is a bit like traditional UNIX where good practice is to typically work as a non-root user but switch to root (e.g. using su) when required, although in this approach the original user need not log out.

A nicer alternative, similar to modern "sudo" approaches in, e.g. Ubuntu, would be for bob to be able to temporarily use higher privileges from within his account, perhaps re-authenticating to ensure this is not done lightly. In the above example, bob might have a drop-down option on the "Save" button to "Save with Programming Rights Enabled" and be required to enter his password to confirm.