Create a new page like the Privacy or Appearance pages but for Wiki details.
All these changes will be emailed.
Needs to include the following options:
* Rename Wiki - Needs to have a box to type the new name in.
* Move Wiki - Needs to have a box to type what you want it moved to.
* Delete Wiki - some sort of check to ensure they actually want to delete the wiki is probably needed - definitely don't have this automatically set! Add a box to describe why they want it deleted / a check that they have community consensus.
@cook879 suggested you could reuse the modal box, since I imagine you enjoyed making it so much...
You can probably get away with extending SpecialFormPage like the Privacy.php file does.