EKS cleanup

[dragonchaser]

EKS cleanup using terraform sometimes results in a ton of leftovers which is a mess if you have to clean it up manually.

Suggestion: update the clean-eks target, add terraform show as last command to see what has been left and make cleaning that up easier.

[viccuad]

We don't lose terraform files and the possibility to delete things by hand, since if a BACKEND=foo-uses-terraform make clean fails on terraform destroy, it will stop there, and you can go to the buildir and run terraform commands.

But a terraform show on failure would be indeed nice. I suppose it would be better if we weren't in this situation anyways, by making github.com/SUSE/cap-terraform more robust.