Initial prometheus config

Also did provision config for grafana, could be done directly but went
through skynet.grafana config

applications/grafana.nix

@@ -24,6 +24,26 @@ in {
         type = types.str;
       };
     };
+
+    ip = mkOption {
+      type = types.str;
+      default = cfg.host.ip;
+    };
+
+    port = mkOption {
+      type = types.port;
+      default = port;
+    };
+
+    datasource = {
+      name = mkOption {
+        type = types.str;
+      };
+
+      url = mkOption {
+        type = types.str;
+      };
+    };
   };
 
   config = mkIf cfg.enable {
@@ -44,6 +64,18 @@ in {
       domain = "${name}.skynet.ie";
       port = port;
       addr = cfg.host.ip;
+
+      provision = {
+        enable = true;
+        datasources.settings.datasources = [
+          {
+            name = cfg.datasource.name;
+            type = "Prometheus";
+            url = cfg.datasource.url;
+            isDefault = true;
+          }
+        ];
+      };
     };
 
     services.nginx.virtualHosts = {