Handle invalid webhook

[wtogami]

https://github.com/slickage/baron
Baron has the "invalid" webhook to handle payments that become invalid. If this happens the admin needs to be notified and the payment removed from adness.

[taesup]

Would this also invalidate the invoice itself as well? At which point, what would be the correct set of actions if a auction payment/invoice were to be invalid?

[wtogami]

The invoice is not invalid, but the payment that was previously confirmed becomes invalid.

This is a lower priority because its occurance would be very rare. Let's deal with this later.