PKCS#11 RPC code (and sharing PKCS#11 login state)

[Stef Walter]

I've taken time to factor out the gnome-keyring PKCS#11 RPC code and put
it into p11-kit. If you're interested, the bug for that is here:

https://bugs.freedesktop.org/show_bug.cgi?id=54105

One of the things that this enables is the ability to run certain
PKCS#11 modules in a daemon and share the login state per desktop
session. Think: login using smart card, and then use smart card with
firefox without entering PIN again.

Obviously it's configurable which modules are treated this way, if any.

This bug tracks the daemon work:

https://bugs.freedesktop.org/show_bug.cgi?id=51949

Cheers,

Stef