Show nicer card/app labels for the card/app tabs

Card, PIVCard:
* Add display serial number to the base class Card

ReaderStatus:
* Try to get the display serial number from scdaemon for all supported
  cards/card applications

PIVCardWidget:
* Show only the display serial number; the full serial number is available
  as tooltip

SmartCardWidget:
* Use display serial number and nicer app names for the labels of the
  card application tabs

GnuPG-bug-id: 5066