Ask for PIV Card Application Administration Key if necessary

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