add OpenSC package

OpenSC is a smart card middleware.
Patches for support of the GnuK USB token have been added.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
add OpenSC's libp11 library

libp11 is a PKCS#11 wrapper library

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
add engine_pkcs11

This adds support for using PKCS#11 modules (such as opensc_pkcs11)
as an OpenSSL engine for RSA.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>