Example contract to allow anyone to extend a subname

[serenae-fansubs]

1. Call approve on the NameWrapper to approve this contract as the "Subname Renewal Manager" for your name
2. Revoke the "Can Approve" permission on your wrapped name

Now any account will be able to extend the expiry for any subname under that name, similar to .eth 2LDs.

No fees (just gas). So this would not be useful to anyone looking to rent subnames for a fee. Instead, this is useful for people who want to issue "forever" subnames (possibly with immutable records too) and then guarantee that they will always be able to be extended, even if the parent owner goes AWOL.