Add confirmation while egpg key delete

[diveshuttam]

'egpg key delete' does not ask for confirmation now, It also deletes $GPG_KEY if the first parameter passed ($1) is empty. It would be better if we ask for a confirmation.

refer EasyGnuPG/egpg#55

[dashohoxha]

There are two issues here.
Create a reminder list so that we can discuss and resolve them at the end.
For the time being let us keep the behavior of egpg unchanged, because this is not the focus of what we are doing currently.

[dashohoxha]

We can close this in favor of this: EasyGnuPG/egpg#55