Add option to delete a yanked release

[hugovk]

What's the problem this feature will solve?

Right now if you want to delete a yanked release, you first have to un-yank that release to be able to delete it.

This gives a small window where people may end up downloading the bad release before it gets zapped.

Describe the solution you'd like

Add an option to delete a yanked release directly without having to un-yank it first.