router: add vnStat service

hosts/router/services.nix

@@ -4,6 +4,9 @@ let
   domain = vars.domain;
 in
 {
+  # vnStat for tracking network interface stats
+  services.vnstat.enable = true;
+
   # https://wiki.nixos.org/wiki/Prometheus
   services.prometheus = {
     enable = true;

renovate.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended"
+  ]
+}