Refactor the Nix config management.

nix-system-configs/modules/secrets/secrets.example.nix

@@ -0,0 +1,19 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}: {
+
+ # TODO Figure out a better way to manage secrets.
+  local.secrets = {
+    gitUserName = "Your Name";
+    gitUserEmail = "you@example.com";
+    codeberg = {
+      username = "your-codeberg-user";
+      password = "your-codeberg-password-or-token";
+    };
+    sshRootPassword = "changeme";
+    tailscaleAuthKey = "";
+  };
+}