Add option for either OR/AND

[c4tz]

Thank you for developing this module.

I think the possibility to decide whether all or just one the modules called by pam_any have to succeed would be pretty nice.

Example 1: I use both howdy and a bluetooth module and only want PAM to accept me if my face gets recognized AND my smartphone is reachable via BT.

Example 2: If I used howdy and a fingerpint reader, I would probably want to only do one of both at a time, so I would need an OR check. (This is already implemented)