Ask the user for the admin key, if the default admin key doesn't work,
i.e. if the admin key has been changed/set.

AuthenticatePIVCardApplicationCommand:
* New command handling the authentication to/of the PIV Card Application

CardCommand:
* Add possibility to cancel a card command

PIVGenerateCardKeyCommand:
* Use new AuthenticatePIVCardApplicationCommand for performing the
  authentication to/of the PIV Card Application

PIVCardApplicationAdministrationKeyInputDialog:
* New simple dialog for asking the user for the hex-encoded PIV Card
  Application Administration Key

GnuPG-bug-id: 4794