Move from features to option based configuration

modules/nix/openssh.nix

@@ -0,0 +1,42 @@
+{ lib
+, pkgs
+, config
+, ...
+}:
+
+with lib; let
+    cfg = config.simmer.openssh;
+in
+{
+    options.simmer.openssh = {
+        enable = mkOption {
+            description = "Whether to enable openssh server";
+            type = types.bool;
+            default = false;
+        };
+
+        port = mkOption {
+            description = "What port the server should run on";
+            type = types.int;
+            default = 22;
+        };
+
+        allow-password = mkOption {
+            description = "Whether the server should allow password authenitication" ;
+            type = types.bool;
+            default = false;
+        };
+    };
+
+    config = mkIf cfg.enable {
+        services.openssh = {
+            enable = true;
+            ports = [ cfg.port ];
+            settings = {
+                PermitRootLogin = "no";
+                PasswordAuthentication = false;
+            };
+        };
+    };
+
+}