feat(server/grafana): add grafana module and enable it on apollo

modules/nixos/server/monitoring/grafana/default.nix

@@ -0,0 +1,30 @@
+{ config, lib, ... }:
+let
+  inherit (lib) singleton mkEnableOption mkIf;
+  inherit (lib.pantheon) mkRootDomain mkPortOption mkStrOption;
+  cfg = config.server.monitoring.grafana;
+in
+{
+  options.server.monitoring.grafana = {
+    enable = mkEnableOption "";
+    url = mkStrOption;
+    port = mkPortOption 3000;
+  };
+
+  config = mkIf cfg.enable {
+    server.networking.ddns.domains = singleton (mkRootDomain cfg.url);
+    server.web-servers.nginx.proxies = mkIf config.server.web-servers.nginx.enable (singleton {
+      source = cfg.url;
+      target = "http://${config.system.hostname}:${builtins.toString cfg.port}";
+      extraConfig.proxyWebsockets = true;
+    });
+    services.grafana = {
+      enable = true;
+      settings.server = {
+        domain = cfg.url;
+        http_port = cfg.port;
+        http_addr = "0.0.0.0";
+      };
+    };
+  };
+}

systems/x86_64-linux/apollo/default.nix

@@ -20,6 +20,10 @@
   };
 
   server = {
+    monitoring.grafana = {
+      enable = true;
+      url = "grafana.bwfiq.com";
+    };
     networking.ddns = {
       enable = true;
       domains = [