modules/services/networking/ssh/sshd.nix: added new boolean options usePAM and passwordAuthentication
modules/services/networking/ssh/sshd.nix: added new boolean options usePAM and passwordAuthentication

Setting both of these options to 'false' configures the OpenSSH daemon to
reject password authentication, i.e. users must have an appropriate key in
~/.ssh/authorized_keys in order to be able to log in.

git-svn-id: 71c8032c709790ec749031c4215f8515ac00dc5a@27732 70bd8c7a-acb8-0310-9f0d-9cc1c95dcdbb

falsifian/personal_nixos,falsifian/personal_nixos,falsifian/personal_nixos,falsifian/personal_nixos,falsifian/personal_nixos