Implement forcekill

[vinicpac]

Implement the example forcekill using elixir.

[Dwctor]

With b1d3cca we now have a fully working Forcekill example within Honey-Potion exclusively. Although the behavior is a bit different (prints killed elements always instead of after 30 seconds) I have deemed that that is close enough to the intended purpose of Forcekill and so will be closing this issue.