Support CACv2 (GSC IS 2.1)

This patch set is implementation of CACv2 interface as specified by GCS-IS 2.1 with an aim to have a working smart card sharing among Linux host and Windows Guest running ActivClient software.

The merge request provides also improved test suite and simple CI integrated in gitlab CI for now, visible in my fork on gitlab:

https://gitlab.com/jjelen/libcacard/

I was trying to make the commits and changes clear, but let me know if something needs some more clarification or improvements.