Migrate to snowfall lib

modules/nixos/system/security/ssh/default.nix

@@ -0,0 +1,9 @@
+{ config, ... }: {
+  programs.ssh = {
+    extraConfig = ''
+      IdentityFile ${
+        config.sops.secrets."${config.hostcfg.hostname}_ssh_priv".path
+      }
+    '';
+  };
+}