refactor: Disable SSH login using password

configuration.nix

@@ -99,9 +99,8 @@ in
   services.openssh = {
     enable = config.selfprivacy.ssh.enable;
     settings = {
-      PasswordAuthentication = config.selfprivacy.ssh.passwordAuthentication;
+      PasswordAuthentication = false;
       PermitRootLogin = "yes";
-      LoginGraceTime = 0;
     };
     openFirewall = false;
 

selfprivacy-module.nix

@@ -108,13 +108,6 @@ with lib;
         type = types.nullOr (types.listOf types.str);
         default = [ "" ];
       };
-      passwordAuthentication = mkOption {
-        description = ''
-          Password authentication for SSH
-        '';
-        default = false;
-        type = types.nullOr types.bool;
-      };
     };
     ###########
     #  Users  #